70 



CEREAL AND FORAGE INSECTS. 



ing in the tip of the ovipositor. Every 40, 50, or 60 seconds the 

 pendent abdomen of the moth is slowly brought forward and upward, 

 and the extensile tip of the ovipositor explores the ins and outs of 

 the upper edge of the egg-mass until the proper notch is discovered, 

 and is held there for a few seconds while the next egg is forced down 

 the oviduct into place. Then the abdomen is carefully lowered and 

 the insect remains motionless for more than half a minute while the 

 egg dries and becomes fixed. The operation of placing the entire 

 supply of eggs occupies normally or under favorable circumstances 

 nearly two hours. The length of time required depends almost 

 wholly on the weather, for moths have been ob- 

 served more than once during a driving snow- 

 storm, nearly buried in snow, late in the after- 

 noon, painfully and with the utmost difficulty 

 striving to complete the morning's task of pro- 

 viding for posterity before the increasing cold 

 should render it hopelessly impossible. 



As the eggs pass from the oviduct they are 

 coated with a brown viscid substance that serves 

 not only to attach them firmly to each other and 

 to the central stem, but may also be necessary in 

 protecting them from the changes of the weather 

 during the nine months that they remain exposed 

 out of doors. This brown coating dries in a few 

 seconds to a brownish pink with a pearly luster 

 that gradually fades under the long-continued ac- 

 tion of the elements. The eggs are so firmly 

 cemented by this substance that the cylinder 

 easily keeps its form after the stem around which 

 it has been built is withdrawn. 



The number of eggs deposited by a female 

 varies exceedingly, and the conclusion has been 

 reached, after repeated observations, that the 

 number depends much upon the favorable or 

 unfavorable food conditions under which the 

 larvse live. Moths produced from caterpillars reared on rank grass 

 contain twice or three times the number* of eggs of those from 

 starved larvae. A dissection of fourteen chrysalids and freshly 

 emerged females gave the following egg counts: 60, 97, 76, 118, 112, 

 97, 97, 90, 177, 162, 122, 113, 129, 140. 



The females evidently oviposit near where they emerge and mate, 

 with the exception of the large contingent that emigrates unmated. 

 The male frequently spends the day where mating took place and 

 remains motionless long after the female has placed her eggs and 

 flown away. (See Plate IY, fig. 1.) 



Fig. 42. — The New Mexico 

 range caterpillar: Female 

 moth in characteristic 

 resting attitude. En- 

 larged. (Original.) 



