82 



PRINCIPAL HOUSEHOLD INSECTS. 



fish, it belongs to the order of insects known as Aptera (wingless), from 

 the fact of their having no vestige of wings throughout life. 



The simple structure of these insects, and particularly their resem- 

 blance to the larval state of wiuged insects, has led to the belief that 

 they are the primitive forms of insect life. That this is true is, however, 

 by no means certain, and they may rather be degraded or debased 

 examples of some of the higher orders of insects. The species figured 

 herewith is not infrequently found in dwellings in Washington, but is 

 apparently undescribed, and, in fact, little is known of the American 

 species. It is, however, closely allied to a European form (L. cervicalis), 

 often found in cellars, and figured by Sir John Lubbock in his mono- 

 graph on these insects (PI. XXV). Another allied European species 

 {Seira domestiea) has been named from the fact of its being a frequenter 

 of houses. 



Fig. 35. — Spring-tail (Lepidocyrtus americanus) 

 view from above (original). 



Fig. 



-Spring-tail (I^ridocyrttis americanus) 

 view from beneath (original). 



These insects belong to the suborder Collembola, which (following 

 Sharp) is distinguished from the other suborder of Aptera, Thysanura, 

 by having but five body segments instead of ten, and possessing a 

 very peculiar ventral tube on the first segment, and commonly also a 

 terminal spring, by means of which these creatures leap with great 

 agility, and from which they take their common name of " spring-tails." 



These insects, though very abundant, have been very little studied, 

 and little is known of their life habits. They often multiply in extraor- 

 dinary numbers, especially in moist situations, swarming on the sur- 

 face of stagnant water or on wet soil. They seem to be very tolerant 

 of cold, and we have interesting accounts of the occurrence of a spe- 

 cies related to the one figured in the Arctic regions on melting snow 

 fields and on glaciers, where they are known as "snow fleas" or " snow 

 worms." Other interesting forms occur in caves, and in the Mammoth 

 Cave in Kentucky they are notably abundant. In houses they may 

 often be found on window sills, in bathrooms, and sometimes, under 



