198 Annals Entomological Society of America [Vol. VI, 



supply the thoracic muscles, and (b) the abdominal nerve 

 trunk, which arises as a stout continuation of the posterior 

 part of the ganglion. This nerve trunk gives off fine branches 

 to the abdominal muscles and on reaching the third abdominal 

 segment, splits into three. 



These three branches supply the reproductive organs, the 

 ovaries or testes, and the ovipositor or the penis. 



Reproductive ' System. 



The male generative organs, (Plate XXII, Fig. 7.) are com- 

 paratively simple in structure. They are however not readily 

 seen in gross dissection until some of the surrounding and 

 over-lying Malpighian tubules are moved. They consist 

 of a penis, ejaculatory duct, vesicula seminalis, and testes 

 with their ducts. 



The testes are smooth, spherical bodies, enclosed in sacs 

 which have deeply pigmented walls, giving them a deep orange 

 color. From the lower end of each testis a delicate tube arises, 

 short and straight, which runs down to join the duct from the 

 opposite side, as the upper limbs of a Y. 



From this junction an exceedingly short length of common 

 duct enters the bulbous upper end of the tubular organ, which 

 would seem to serve as a vesicula seminalis. This is a flexible 

 tube, often seen lying with one or two U-shaped bends in its 

 course. At its upper end this vesicula seminalis is bulbous, 

 gradually narrowing below to form the ejaculatory duct, (Fig. 

 7, e. d.), which crosses the rectum dorsalh^ from left to right, 

 to enter the penis in front of it. 



The female reproductive organs, (PI. XXII, Fig. 8) are .of the 

 house fly type. There are two ovaries, each consisting of 

 some 60 ovarioles. The ovaries vary in size according to the 

 degree of maturity of the lowest ova, of which there are never 

 more than four in a single ovariole. In some cases the ovaries 

 occupy more than half of the whole abdominal space. The 

 ovarioles from one side open into a wide tubular duct which 

 joins the similar duct from the other side like the arms of a Y. 



As a result of this junction a common oviduct (o. v.) results, 

 which runs down forming a long third limb to the Y. Below 

 the attachment of the uterine appendages the oviduct con- 

 tinues as the uterus. The appendages consist of the uterine 

 glands and the receptacula seminis. 



