576 



ZOOLOGY 



SECT. 



muscles (obi. stern.}, confined to the abdomen: (3) and longitudinal 

 tergal muscles, best developed in the abdomen. The various 

 segments of the limbs are capable of being flexed or extended on 

 one another, as in the Crayfish, by the contractions of special 

 muscles. The \vings are little used, the female cockroach being 

 incapable of flight, and the male nut a strong flier, and accordingly 

 the wing muscles are not very strongly developed. 



Between the body wall and the alimentary canal is a cavity 

 taking the place of the coelome, but in reality forming a specially 



lh- s-alrec t&3 



cer 



sat.da, tnor.ga.ry 

 nf.gra.nff 



FIG. 457. Semtdi^rammatic view of the internal organs of a female Cockroach, dissected 



e left side. The heart is 11, .t represented. ?,</.!, aW.5 first and fifth abdominal segments 



anus; ant. anteimary nerve: brn. brain; cer. anal cercus : ca>c. .-.. ,-;, ; coll. colleterial 



. crop; ./-::. gizzard; gon. gmiain.phy.-es; inf,-. gang, sub-cesophageal {fang-lion- 



ift. mi. -tine ; Ib. pip. labial IK,]), ; /.or. left ..vary ; ,,talp. nialpighian tubes ; mx.plp. niaxillnrv 



palp.; od, points to the external opening of the median oviduct (vagina); ces. oesophagus; 



v. ngnt ..vary; sal. gld. salivary glands ; sal. rec. salivary receptacle (left) ; sal. du. salivary 



luets, mdicatmg the ].,.,nit at wliich the median duet of the salivary glands unites with the 



median duet of the salivary receptacles ; spir. spiraek- ; .< 7, sternum ,,f the seventh seg- 



. 10, tergum of the tenth segment ; t/,1, tic-, th*. first, second, and third segments of 



the thorax. 



developed part of the blood-vascular system (ha?moccele). This 

 bounded externally by an irregular wall, formed of a mass of 

 polygonal cells constituting the fat lody. 



Digestive system. The mouth' opens into a buccal cavity, 

 which receives tin- ducts of the stdimnj glut, Is (Fig. 457, sal. '//</.). 

 Each -land is divided into twu lubes. 'each made up of numerous 

 ramifications. In close ivlati.ni to each gland is an elongated 

 thin-walled sac the salivary receptacle (sal. rec.). The duct given 



' tr Tht ' salivary receptacle joins thai of the opposite side, 



the median duct thus formed is joined by a single du<-t (sal 



