458 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 



There is a pair of ovaries, lying symmetrically right and left in 

 the abdomen dorsal to the stomach. Each ovary consists of a 

 number of ovarian tubes or ovarioles ; usually four on each side, 

 but in one of my mounted preparations there are five ovarioles in 

 each ovary. The ovarioles are of the simplest type, composed of 

 successive egg-chambers, increasing progressively in size, without 

 special yolk-chambers. The ovarioles of each side unite into a 

 short paired oviduct, and the paired oviducts of the two sides 

 unite into a median unpaired oviduct, in which, probably, the 

 ovum is fertilised and subsequently becomes invested by a shell. 



In addition to the ovaries and oviducts, which are very easy 

 to dissect out, there lies, ventral to the rectum, an organ found 

 in all fertile female insects, the receptaculum seminis, into which 

 the sperm is received at copulation and stored up in order to 

 fertilise the eggs as required. The receptaculum and its duct 

 are by no means difficult to dissect out and mount, and make a 

 singularly beautiful and fascinating microscopic preparation 

 (PI. 31). The duct is coiled up into a veritable labyrinth, and the 

 sole difficulty in the dissection is to uncoil it without breaking it. 

 The receptaculum itself (R.S.) is a chitinous capsule with a 

 brown, delicately sculptured, semi-transparent wall, and a peculiar 

 form. The main portion of the capsule, that portion from which 

 the duct arises, is roughly spherical in form. At one point, which 

 is distant from the origin of the duct by about one-third of the 

 circumference of the main chamber, an outgrowth or diverticulum 

 arises, forming a second chamber, which is horn -shaped, and 

 bends round the main chamber. The horn-shaped chamber is 

 connected, on its concave side, to the main chamber by a sheet of 

 striated muscle (m.r.s.). The contraction of these muscle-fibres 

 must clearly have the effect of approximating the horn-shaped 

 chamber to the main chamber, and at the point where the 

 horn-shaped chamber arises from the main chamber there is a 

 rim of chitin which appears to be softer than the rest of the wall, 

 forming a weaker spot which apparently serves as a hinge, 

 allowing the horn-shaped chamber to be moved slightly ; it is at 

 this spot that artificial deformations of the wall of the capsule 

 are often caused as the result of slight shrinkage when the 

 receptaculum is mounted in Canada balsam. The receptaculum 

 is usually packed with spermatozoa, which can be seen through 

 the wall of the capsule, but better still if the capsule be burst 



