THE CATERPILLAR AND THE MOTH 



The stomach is contracted to a mere remnant of its 

 former size (A, Vent), and its walls are thrown into thick 

 corrugations. The intestine (Sin/) is about the same as 

 in the earlier stage of the moth (B). 



Since the moth of the tent caterpillar probably eats 

 nothing, it has little use for a stomach. The intestine, 

 however, must serve as an outlet for the Malpighian 

 tubules (Mai), since the latter remain functional through 

 the pupal stage. The secretion of the tubules contains 

 great numbers of minute spherical crystals, which accumu- 

 late in the rectal sac (Red) where they form the orange- 

 colored mass contained in this organ and discharged as 

 soon as the moth leaves the cocoon. 



Most of the male moths of the tent caterpillar emerge 

 from the cocoons several days in advance of the females. 

 At this time their bodies contain an abundance of fat 

 which fills the cells of the fat tissue as droplets of oil. 

 This fat is probablv an energy-forming reserve which the 

 male moth inherits from the caterpillar, for the internal 

 reproductive organs are not yet fully developed and do 

 not become functional until about the time the females 

 are out of their cocoons. 



The bodies of the female tent caterpillar moths, on the 

 other hand, contain little or no fat tissue; but each female 

 is fully matured when she emerges from the cocoon, and 

 her ovaries are full of ripe eggs ready to be laid as soon as 

 the fertilizing element is received from the male (Fig. 165, 

 Ov). The spermatozoa will be stored in a special recep- 

 tacle, the spermatheca (Spm), which is connected with the 

 exit duct of the ovaries (Vg) by a short tube. Each egg 

 is then fertilized as it issues from the oviduct. The ma- 

 terial that will form the covering of the eggs when laid is 

 a clear, brown liquid contained in two great sacs (Fig. 

 165, Res) that open into the end of the median oviduct 

 (Vg). Each sac is the reservoir of a long tubular gland 

 (CIGl). The liquid must be somehow mixed with air 

 when it is discharged over the eggs to give the egg covering 



[311] 



