THE FEMALE REPRODUCTIVE ORGANS 



489 



ure, being armed with hooks and projections and affording excellent 

 specific characters. It can be seen in place without dissection by 

 drawing back the orbicular convex piece called the velum 2^>enis. 



In the Hymenoptera the reproductive system is quite simple, as 

 seen in Fig. 462. 



The general shape and relations of the female reproductive organs 

 are seen in Fig. 298, of the locust (Acrydiidte). The ovaries consist 

 of two large bundles of tubes, each bundle tied to the other by slight 

 bands, with air-sacs and tracheae ramifying among them. These tubes 

 extend along the intestine, passing into the pro- 

 thorax. The ovarian tubes opening into the 

 oviducts unite to form the vagina, which lies 

 on the floor of the abdomen. (In the cockroach 

 the vagina has a muscular wall and chitinous 

 lining.) Above the opening of the duct, and 

 directly communicating with it, is the copulatory 

 pouch (bnrsa copulatrix), a capacious pocket lined 

 within with several narrow, longitudinal, chiti- 

 nous bands. Behind the bursa copulatrix lies, 

 partly resting under the fifth abdominal gan- 

 glion, the sebific, cement, or colleterial gland 

 (colleterium ; compare Fig. 299, sb), which is 

 flattened, pear-shaped, a little over half as long 

 as a ripe egg of the same insect. From the 

 under side, a little in advance of the middle, 

 arises the sebific duct, which, after making three 

 tight coils next to the ganglion, passes back and 

 empties into the upper side of the bursa copula- 

 trix. dilating slightly before its junction with the 

 latter. 



The most primitive type of reproductive organs observed in insects 

 is that of the young Lepisma and the Ephemeridse, in which the 

 outlets of the oviducts and of the vasa defereutia respectively are 

 double or paired, showing that insects have probably inherited these 

 structures from the segmental organs of their verrnian ancestors. 



Eeaumur had already observed the process of oviposition and seen 

 that the female Ephemera had two openings near the end of the 

 "6th" abdominal segment, from which he saw two masses of eggs 

 pass out at a time (Fig. 463). Eaton afterwards (1871) referred to 

 the oviducts as terminating between the 7th and 8th segments of the 

 abdomen, and after him Joly ; but for a detailed monograph on the 

 subject we are indebted to Palmen. He found that the outlets of 



FIG. 462. Male or- 

 gans of saw-fly (Ailialia 

 centifoliif') : <>, <i, testes ; 

 b. b, epididymis ; o, d, 

 vas deferentia ; e, vesicu- 

 lif seininales ; /, ductus 

 ejaculatorius ; h, penis 

 (see also p. 180). After 

 Newport. 



