18 



CEREAL AND FORAGE INSECTS. 



HIBERNATION. 



The insects pass the winter in the adult stage. In November, 1908, 

 careful search was made, during several days, in the cornfields* for larva? 

 and pupae, but none could be found, though there were plenty of adults 

 present. This is not proof but a good indication that they pass the 

 winter only as adults. Nothing, of course, is known of the eggs as 

 thev occur in the fields. 



CHARACTER OF GROUND MOST LIABLE TO INFESTATION. 



Larvse, pupae, and adults seem to confine themselves to low, swampy, 

 peaty soils that remain moist the entire year. During a verv dry 



Fig. 10.— Structural characters of Clivina, impressifrons: a, Ventral aspect of head and mouth parts; b, 

 maxilla; c, parts of labium; d, fore leg; e, middle leg; /, hind leg. Much enlarged. (Original) 



period they have only a short distance to go below the surface to find 

 plenty of moisture. Professor Webster states that he has observed 

 them in great numbers, floating on the surface of the water in corn- 

 fields in Illinois, immediately after heav}^ rains. Mr. W. C. Strom- 

 berg, Galesburg, 111., states: 6 



At another time a friend of mine turned up a nest of Clivina impressifrons. It was 

 in early spring. They were clinging to the underside of a log which was very deeply 



Cir. 78, Bur. Ent., U. 8. Dept. Agr. &Ent. News, vol. 



4, p. 150, 1893. 



