412 SUJIMAUY OF CUURKNT UESKAUCIIES RELATING TO 



(1) poiutcd tactile hairs ; (2) sensorial clubs ; (3) sciisoriiil liairs, iin- 

 beililed in a longitudinal depression (at times scarcely visible) and 

 often transformed into ridges or plates. The latter portion of tbo 

 pa])er is devoted to a description of now or little known species. 



Spinning Glands of Saw-flies.* — These arc described by M. N. 

 Poletajew. Each of the two glands (which lie ventrally and mcsially 

 in the body-cavity) is made up of a number of small chitinous bodies 

 filled with silk-])r()ducing cells. These bodies arc more or less 

 aggregated, and their respective ducts unite into a common duct near 

 the labium and then form the spinning apparatus. The common 

 canal is horseshoe-shaped in si ction, and through its centre issues 

 the single thread. In larval Lepidoptera the thread is not single, 

 but composed of two twisted threads, and hence Poletiijcw concludes 

 that Helm and Corualia are wrong in asserting that union of the two 

 ducts takes place before the spinning ajjparatus is reached. 



Alimentary Canal of Insects.! — The researches of M. IT. Beaure- 

 gard deal with the genera Cantltaris, Epicatita, Lijita, itc. lie distin- 

 guishes three regions: (1) oesophagus, (2) stomach, (3) intestine; 

 these are sei^arated from each other by two valves ; the structure of 

 the most anterior of these two valves, termed the " cardiac," appears 

 to dilfer in ditfercnt genera ; the form of the cells is characteristic of 

 the several regions of the gut. The author intends to publish a more 

 detailed description of all these fticts. 



Scales of Coleoptera.J: — Mr. G. Dimmock describes the scales or 

 scale-like hairs of a number of beetles, and the effects of scales on the 

 coloration of these insects and the modes of coloration of scales them- 

 selves. Scale-like hairs of Ciciiulcla, Anthrenits, Ilajjlia, PoIi/phyUa, 

 Vahjus, Psiloptera, Chalcolcpidins, Alaus, an undetermined genus of 

 Elatcrida3, Ptinns, Cli/tus, and Entimus were used. This adds the 

 ElateridjE and Cerambycida) to the families already recorded as some- 

 times owing their configuration to a scale covering. 



The question of the morphological identity of scales and hairs of 

 insects has been long since settled, so that the question of whether 

 an appendage is a scale or hair has little importance. The extremely 

 minute spines or hairs upon the wings of diptera, hymenoptera, and 

 other insects are simply another form of scales. It is only in insects 

 where certain kinds of brilliant coloration have been developed that 

 one finds scales. This leads to a consideration of how hairs and 

 scales of insects affect coloration. They may simply cover a surface 

 of the same colour as their own ; in such cases hairs may, according to 

 the angle in which they stand, theii- abundance, or their length, give 

 rise to appearances which we designate as pubescent, velvety, pilose, 

 sericeous, &c. ; scales under similar circumstances may give rise to 

 similar appearances, but arc most often imbricated an<l usually cause 

 more lustre than hairs. Hairs or scales may be of a different colour 

 from the surface on which they are j^laced. If they arc numerous and 



* Zool. Anzeig., viii. (1SS.^) pp. 22-3. 



t Compter Kuiidiis, xcix. (ISSI) pp. 1083^6. 



X Tsycbc, iv. (1S83) pp. 3-11, 23-7, 43-7, (;3-71 (11 %8.). 



