162 AN INTRODUCTION TO ENTOMOLOGY 



The spermatophores. — In some insects the spermatozoa become 

 enveloped in a sac in which they are transferred to the female; this 

 sac is the spermatophore. Spermatophores have been observed in 

 Gryllidae, Locustidae, and certain Lepidoptera. 



Other structures. — A ligament of the testis, corresponding to the 

 ligament of the ovary, is often present ; the common outlet of the testi- 

 cular follicles, corresponding to the oviduct is termed the vas deferens 

 (Fig. iSi, vd); an enlarged portion of the vas deferens serving as a 

 reservoir for the products of the testis is known as a seminal vesicle 

 (Fig. i8i, sv); the invaginated portion of the body- wall, correspond- 

 ing with the vagina of the female, is the ejaculatory dtict (Fig. i8i, ed); 

 accessory glands, corresponding to the colleterial glands of the female, 

 are present (Fig. i8i, ag); the function of these glands has not been 

 determined, they may secrete the fluid part of the semen, and they 

 probably secrete the spermatophore when one is formed; the penis, 

 this is merely the chitinized terminal portion of the ejaculatory duct, 

 which can be evaginated with a part of the invaginated portion of the 

 body-wall. It is furnished with powerful muscles for its protrusion 

 and retraction. 



XVI. THE SUSPENSORIA OF THE VISCERA 



The organs discussed here do not constitute a well-defined system, 

 but are isolated structures connected with 

 different viscera. As in most cases they 

 appear to serve a suspensory function, they 

 are grouped together provisionally as the sus- 

 pensoria of the viscera. 



The dorsal diaphragm. — This is a mem- 

 branous structure which extends across the 

 abdominal cavity immediately below the 



_. „ ^. heart, to which it is attached along its median 



i'lg. 182. — Diagram show- a>i. 1 ^ 1 • r ^.i.- j- u 



ing the relation of the h^e. i he lateral margms 01 this diaphragm 



do.-sal diaphragm and are attached to the sides of the body by a 

 the ventral diaphragm ... , , . , • 1 1 



to other viscera; a, series of triangular prolongations, which have 



ahmentary canal; d, been commonly known as the wings of the 



dorsal diaphragm; h, , .^. n ^1 1 , i- 1 



heart; n, ventral nerv- heart (Fig. I ^g, c). The dorsal diaphragm IS 



ous system; v, ventral composed largely of very delicate muscles, 

 diaphragm. -r , • ,1 ■ ■^^ 1 , .1 



Its relation to the heart is illustrated by the 



accompanying diagram (Fig. 182, d). 



There are differences of opinion as to the function of the dorsal 



diaphragm. An important function is probably to protect the heart 



