DIVISION OF ENTOMOLOGY. 7 



which, together with the posterior end of the vapiia itself, form the 

 structure commonly named the bursa copulatrix. Fig. 5. The drawings 

 of Snodgrass and Swammerdaiii just mentioned, liowover, show clearly 

 the relation of the large pair of ovaries and the pair of oviducts leading 

 into the common median vessel or vagina — also the globular seminal 

 receptacle^ or spermatheca, with its attendant white accessory glands. 

 The common duct of these little glands passes around underneath the 

 spennatheca, where, in conjunction witli the latter, it connects with the 

 upper end of the short spermathecal duct which, in turn, opens through 

 the dorsal wall of the vagina \ery close to its anterior end. Swammer- 

 dam has represented the spermatheca pushed to one side in an attempt 

 to show its duct connecting with the dorsal i^art of the vagina. 



b. ORGANS OF THE DRONE. 



Snodgrass has given the most instructive and accurate illustration 

 of the reproductive organs of the drone, natural position, dorsal view, 

 in his Pig. 56, A. Briefly, they consist of the penis, the ejaculatory 

 duct and a set of paired organs — the testes, the vasa deferentia, the 

 vesiculae seminales and, finally, the accessory mucous f/lan-ds. The lat- 

 ter are connected by the slender ejaculatory duct with the large in- 

 vaginated penis which lies entirely within the abdomen along the 

 median line between the paired organs. Of this latter set of 

 organs, the accessory miicous glands are the larger. They have the 

 form of two long sacs, slightly constricted near the middle, having the 

 blunt closed ends turned anteriorly. The narrowed posterior ends of 

 the glands bend toward each other and meet on the median line close 

 above the base of the penis at the extreme caudal end of the body. The 

 walls of these glands, at the blunt rounded ends, are comparatively 

 thin (Fig. 6). Beginning at the region of the constriction, however, the 

 walls gradually become much thicker posteriorly, due principally to 

 the presence of a greater number of muscle fibres. In the region of 

 greatest muscularity, the fibres are arranged more or less regularly 

 into three layers. Figs. 7 and 8 are photomicrographs of a cross section 

 made about one-fourth the length of the gland from its posterior end. 

 They show on the outside a layer of longitudinal fibres; immediately 

 within that, circularly arranged fibres; and, finally, within that next 

 to the glandular cells lining the lumen, a layer of longitudinal fibres 

 marked "c." The lumen of the gland is usually packed to distention 

 with a white granular homogeneous fluid. The active spermatozoa 

 originate in the pair of testes and pass through the coiled vasa defer- 

 entia into the long narrow, cylinder-like, curved vesiculae /.eminales or 

 seminal vesicles there to be stored in quantity. The vesicle walls are 

 muscular throughout their length, and of about uniform thickness. 

 Lying upon the basement membrane of the cells lining the lumen of 

 each vesicle (Figs. 13 and 14) is a layer of circularly arranged muscle 

 fibres which are cut lengthwise in cross sections of the organ itself. 

 Next outside the circular layer is a somewhat thicker layer of longi- 

 tudinal fibres, and outside of that is an enxelope consisting mostly of 

 loose circularly arranged connective tissue fibres and muscle fibres in- 

 terwoven with many small tracheae. The right and left seminal vesicles 

 each connect by short bent ducts with the narrowed bases of the cor- 



