Typical Histologic Features of Tunga penetrans in Skin Biopsies

Context.—Tunga penetrans is a flea that burrows into human skin, causing the disease tungiasis. Although the parasite is not endemic in the United States, patients may present with this disease upon returning from tropical locales. Histologic sections contain a variety of flea parts that may present a diagnostic dilemma for pathologists unfamiliar with this disease. Objective.—To determine the typical histologic features of T penetrans in biopsies from patients with tungiasis. Methods.—We reviewed biopsy specimens from 7 patients with tungiasis and sought 8 distinct structures: the exoskeleton, hypodermal layer, respiratory tract (tracheae), digestive tract, striated muscle, head, posterior end, and developing eggs. Results.—The exoskeleton, hypodermal layer, tracheae, digestive tract, and developing eggs were present in all biopsy specimens reviewed. Striated muscle, the posterior end, and head, however, were present in 57%, 43%, and 0% of the biopsies, respectively. In addition, we noted a unique, pale-staining layer in the exoskeleton at the posterior end of the organism that, to the best of our knowledge, has not previously been described and that may be of diagnostic value. Conclusions.—Despite the absence of 3 key morphologic features in many (posterior end and striated muscle) or all (head) of our biopsies, the exoskeleton with a hypodermal layer, tracheae, and developing eggs were uniformly present, and together these features are sufficient for a diagnosis of tungiasis.

Development of pollinium in Malaxis muscifera (Lindl.) Kuntze

Anther primordium of Malaxis muscifera (Lindl.) Kuntze initiated as a homogenous mass of meristematic cells is surrounded by protoderm. Two thecae are oriented towards the labellum, each of them consisted of a mass of archesporial cells. The hypodermal layer of sporogenous cells divide periclinally to form an endothecial, a middle layer and a tapetum. Pollen mother cells formed different types of microspore tetrads. Each microspore divides mitotically resulting a generative and a vegetative cell. Degeneration of the sterile septum resulted four naked and clavate pollinia. Key words: Malaxis muscifera; Anther; Pollinium; Morphogenesis DOI: 10.3329/bjb.v39i2.7480 Bangladesh J. Bot. 39(2): 193-198, 2010 (December)

The “Hemizonid,” a Hitherto Unrecorded Structure in Members of the Tylenchoidea.

During the detailed study of the finer anatomical structure of the potato tuber nematode, Ditylenchus destructor Thome, 1945, the presence of an apparently hitherto unrecorded structure was revealed. It is situated on the ventral surface of the body just anterior to the excretory pore. It is quite easily seen in living nematodes and has no doubt, in the past, been confused with the excretory pore. It appears as a bright lens-like structure, more highly refractive than the neighbouring parts, especially when specimens are viewed in an approximately lateral position. The structure is really band-like, usually more or less biconvex in section, situated between the cuticle and hypodermal layer.

B—On the structure of the scent organs in the male E. core asela

My friend, Professor Sir Edward Poulton, F. R. S., has handed me a copy of Mr. O. H. Latter’s account of his observations on the courtship of the butterfly Euplœa core asela , and the accompanying use of the scent-brushes of the male. We are deeply indebted to Mr. G. M. Henry, of the Colombo Museum, for a supply of material of the species, carefully preserved and packed, from which the sections here described have been made. As will be learned from Mr. Latter’s paper and the references therewith, special scent-organs in male insects are of frequent occurrence and have long been known. The organs in Euplœa are not of an unusual character, but Mr. Latter’s observations are entirely new, and show that the scent-apparatus is used, at least in this species, to attract the female from a distance . This function, which I venture to term telegamic , has not hitherto been recognized except perhaps in moths of the genus Hepialus , in which the action occurs over only very short distances. The scents produced by male insects have been supposed to be rather of an aphrodisiac character, coming into play only when contact, or at least proximity has been attained. Many female moths produce a directive scent, invariably, so far as is at present known, imperceptible to the human sense. Male moths will fly from great distances (experimentally for more than a mile) in response to its stimulus. Such females as have been microscopically examined do not possess special glands for the secretion of these directive odours. The whole hypodermal layer underlying the terminal segments of the abdomen is modified into a secreting epithelium, and the scent appears to be diffused by osmosis. Even among day-flying moths, sight does not appear to be an important factor in the communication of the sexes. In the majority of the butterflies, however, sight seems to be of first importance, though the butterfly’s eye is not more highly developed than is that of most moths. Whilst scent organs of considerable complexity are of continual occurrence in moths, they tend to be of a simpler character in butterflies, being usually in the form of special wing-scales which secrete a scent, frequently perceptible to the human sense. Nothing corresponding with the directive odours of female moths has so far been observed in butterflies, and of those species in which scent organs have been found, they occur only in the males, except when the odours produced are defensive, when they may be found in both sexes, as in the genus Heliconius . A high development of male scent-organs is, however, found in the Danaine butterflies, and especially in the genus Amauris , the species of which have active scentglands in the hind wings and extrusible abdominal brushes. Müller, in 1877, suggested a possible correlation between the brushes and the wing-glands, but it was not until 34 years later that the actual application of the brush to the gland was observed by Lamborn in Africa. A peculiar feature in some species is that a dust is formed by the breaking up of specially secreted fine hairs which pulverize into small particles. This dust may be formed either in the brush, as in Amauris psyttalea , or in the wing-glands, as in those species in which the gland is in the form of a pocket.