" ADAPTATIONS " TO SOCIAL LIFE : THE TERMITES 



(ISOPTERA) 



By THOMAS E. SNYDER, Ph. D. 

 bureau of entomology, u. s. department of agriculture 



(With Three Plates) 

 INTRODUCTION 



GREGARIOUS LIFE 



Many insects are gregarious feeders, Lepidopterous and saw- 

 fly larvae, Hemiptera, and Orthoptera furnishing notable examples. 

 Others live together in large numbers, possibly due only to the fact 

 that the eggs were laid in a mass or close together, as in the case 

 of certain wood-boring beetles ; these are mere temporary associa- 

 tions. Again, certain adult insects congregate solely for the purpose 

 of mating ; for example, mayflies, mosquitoes, and gadflies. Par- 

 ticularly striking is the habit of the large gadfly {Tabanus amcricaniis 

 Forster) as noted by Mosier and Snyder in the lower Florida Ever- 

 glades where the males congregate in enormous numbers to mate with 

 the females just before dawn. Still other insects have the habit of 

 congregating in large masses for special purposes ; for example some 

 Lepidopterous larvae which build webs and live together in them 

 for protection. But in practically all cases, except among the true 

 social insects, the congregating is more or less temporary and is 

 due to hunger, sex or fear, or to combinations of these elemental 

 motivations, although sometimes caused by undue increase in num- 

 bers and the necessity for migration. In but few instances can there 

 be traced any modifications which one could say result from such 

 a life, 



THE DAWN OF SOCIAL LIFE 



In a few exceptional cases, notably among wood-boring insects, 

 there is really a beginning of a true social or colony life and this 

 can be seen in the case of some of the roaches, the wood-boring 

 beetle, Parandra hrimnea Fab., the paedogenetic beetle MicrouwlfJius 

 debilis Lee, and species in the peculiar order Zoraptera. in which 

 there appears to be the foundation of a caste system. 



Smithsonian Miscellaneous Collections, Vol. 76, No. 12. 



