178 DR. V. E. SHELFORD ON THE LIFE-HISTORIES AND 



D. Food. 



The food o£ the larvae consists o£ land Crustacea, centipedes, spiders, 

 <lrao-onflies, butterflies, flies, beetles, and larvae of all sorts, in fact any small 

 animals that come within reach. If the larvae are not fed, they will not die 

 for a week or two, or even longer, but the lengths of their periods of growth 

 are greatly increased. 



It has been noted that pupse which emerge late in the season and which 

 have been in the warm vivarium for a period of two or three months, are 

 much smaller than those that appear at the usual time of the species. This is 

 probably due to an acceleration of physiological processes without sufficient 

 feeding. 



As was pointed out in connection with the larvae of C. lepida, the burrow 

 is of such a type (PI. 24. fig. 19) that the sand closes it and the larva is 

 unable to feed during much of the time. The larval life is two years and the 

 imagoes are small. C. generosa, on the other hand, has an especial arrange- 

 ment for keeping the burrow open (PL 25. figs. 22-24), and the larval life 

 is one year and the imagoes large. Whether or not this time difference is 

 related to food conditions, is uncertain. 



E. Relation of Habits and Responses of the Adults to the Environmental 

 Conditions of the Young Stages. 



1. Sexual Maturity and Mating. 



None of the species which hibernate reach sexual maturity in autumn. 

 If the eggs were laid at this time the larvae would not be able to feed and 

 store up enough food to enable them to withstand the winter conditions. 

 The imagoes show no tendency to copulate until after a number of the warm 

 days of spring have passed, and mating takes place only on warm and usually 

 sunny days. 



2. Egg-laying. 



Species which lay in hard soils like humus or clay, are able to do so only 

 when it is moist. Accordingly, during a dry period they select a place near a 

 spring or brook where the moisture is adequate. On the approach of the 

 wet weather, the larvae will accordingly be subjected to extremely moist 

 conditions or may be destroyed by high water or other disturbances. During 

 a wet period such species lay in higher and dryer places. If a dry period 

 follows, the larvae will be subjected to extremely dry conditions, and if the 

 surface of the soil becomes very dry soon after the laying of the eggs, 

 the larvae may not be able to make their way to the surface, and accordingly 

 starve (see p. 161). 



