ZOOLOGY AND BOTANY^ MICROSCOPY, ETC. 205 



hairs, beneath which are a number of glandular epithelial cells. They 

 have no special muscles. The function of these bodies is probably that 

 of a stink-organ. 



Mr. Minchin gives a somewhat different account of the structure of 

 the hypodermis than that which is found in Miall and Denny's work 

 on the Cockroach. He finds that the hypodermis does not consist of a 

 single, but of two layers of cells, except where the cuticle is folded to 

 form an articulation, when the upper alone remains. In certain parts 

 the cells of the lower layer become giant-cells, and are undoubtedly gan- 

 glionic ; they are extremely abundant in the fore-part of each tergum. 

 The nerve-end cells are probably connected with a seta where the terga 

 are exposed, but where these are overlapped they seem to be merely 

 connected with small papillae. 



New Mode of Closing Trachese of Insects.* — M. G. Carlet describes 

 a mode of closing the trachese of insects which has been hitherto unde- 

 scribed. He calls it " fermeture operculaire." In the Hymenoptera 

 there is between the genital armature and the integument a piece which 

 he calls the fenestrated scale, as it is pierced by a large stigma. Within 

 this stigma the trachea resembles one of the baskets with an oblique 

 cover which are carried by fishermen. A tracheal muscle is spread on 

 this cover (operculum) ; when the latter is raised, the trachea is closed 

 and its contents isolated from the outer air. 



New Organ of Hymenoptera.t — M. G. Carlet has found it difficult 

 to understand how the sting of Hymenoptera, or even the movements of 

 respiration, can fail to affect injuriously the delicate tracheal apparatus 

 described in the preceding note. He has now, however, found a new 

 organ, which he calls the coussinet ; this has a plano-convex form and is 

 fixed by its plane surface against the anal scale, while its convex side 

 answers to the portion of the fenestrated side not occupied by the tracheal 

 apparatus. By its means this last is kept free from the anal scale ; the 

 operculum is in contact with no other piece of the poison apparatus, and 

 may be raised or depressed freely by the contraction or relaxation of the 

 tracheal muscle. This new organ is composed of spheroidal cells with 

 granular protoplasm, which are connected with one another by a fine 

 and transparent chitinous substance ; this last connects the mass of cells 

 with the anal scale. It may be said to form a pivot for the poison 

 apparatus, the movements of which it facilitates. 



Male Copulatory Apparatus of Pompilidae.J— General Eadoszkowski 

 finds that the structure of the copulatory apparatus of the genera of this 

 family of Hymenoptera is of a common type. He considers it under 

 the five heads of preparatory apparatus, forceps, basilar piece, genital 

 operculum, and genital palpi. 



The preparatory apparatus is composed of two bodies united by a 

 membrane which it is very difficult to detach ; the hooks are more or 

 less elongated, and their terminations may be rounded, or cut sharply 

 off, or forked. The forceps is composed of a long and wide arm, which 

 is always provided with hairs, of a basal piece of varying form, and of 

 a " volvella," at the base of which are two or three teeth. The basilar 

 piece is always more or less large. The genital operculum is composed 



* Comptes Rendus, cvii. (1888) pp. 755-7. f T.c, pp 955-6 



X Bull. Soc. Imp. Moscou, 1888, pp. 462-93 (4 pis.). 



