Whiting: Rearing Meal Moths 



261 



THE PUPAE APPEAR LIKE MINUTE WAXEN IMAGES 



And they may be separated as regards sex and eye color. The photograph shows in order: 

 the dorsal view of a black eyed female with ovipositor visible (the appendage at the bot- 

 tom); dorsal view of an orange eyed male; and ventral view of a black eyed male showing the 

 characteristic male antennae. The orange eye color is a Mendelizing difference from the 

 black, (about xl7) (Fig. 20.) 



it will come to rest at the drop from 

 which it engorges itself. At ordinary 

 room temperatures it is necessary to 

 feed the wasps every other day, but if 

 it is desired to keep any individuals 

 isolated for an extended period it is 

 better to feed them once and set them 

 in the ice chest. 



OBSERVE COCOONS CAREFULLY 



At eclosion both males and females 

 are either mature sexually or almost so, 

 consequently females are certainly 

 virgin only if males are not present. 

 In obtaining virgin females, pupae 

 should be isolated or great care should 

 be taken to see that no mature wasps 

 are present in the culture. The insects 

 have the habit of crawling back into 

 cocoons after eclosion. For this reason 

 it is important to see that cocoons are 

 either empty or intact. 



After stinging the caterpillar the 

 female deposits no eggs until her victim 

 has become torpid. Eggs are placed 

 on top of the caterpillar or underneath 



and may be easily observed. There is 

 no danger of contamination from the 

 food (even if wasps have infested the 

 caterpillar culture) for eggs are never 

 laid except upon torpid and flaccid 

 hosts. Such should of course be dis- 

 carded in selecting caterpillars for the 

 culture vials. 



Maggot-like larvae emerge very 

 shortly from the eggs and cling to the 

 integument of their host. Growth is 

 rapid and soon white cocoons are spun, 

 attached firmly to the glass. The cater- 

 pillars are reduced to shrivelled rem- 

 nants which are often shaken into the 

 etherizing bottle with the first count of 

 wasps. Hadrobracon is much more 

 resistant to ether than is Drosophila and 

 very much more resistant than Ephes- 

 tia. It is usually safe to let one lot of 

 wasps remain in the etherizing bottle 

 while another lot is being counted. 



If males only are desired they may 

 be obtained parthenogenetically from 

 virgin females. Mated females pro- 

 duce both males and females. 



