47 



and herbage. The adults are known to eat plant-lice, small caterpil- 

 lars, and grasshoppers' eggs. This mite is thus an important preda- 

 ceous member of the association. The dragon-flies are well known to 

 feed upon small insects, which they capture on the wing, and on ac- 

 count of their abundance they are influential insects here. 



An examination of the list of animals secured at this station 

 shows that there is considerable diversity in the conditions under which 

 their breeding takes place. Indeed the breeding habits and places are 

 almost as diverse as are the feeding relations. Thus the snail Galba 

 breeds in the water; and the crawfish, Cambarus gracilis, lives as a bur- 

 rower except for a brief period in spring, when it is found in streams. 

 It is distinctly a subterranean species. The garden spider, in the fall, 

 leaves its eggs in its web. The life history of the ambush spider is not 

 known. It seems probable that the sexes meet upon flowers, and as 

 the flowers fade they migrate to fresh ones — a response which Han- 

 cock has observed ('n : 182-186) in the allied species Misumena 

 vatia. The ambush bug, when found on flowers, is in a large number 

 of cases copulating, but where the eggs are laid and the young devel- 

 oped is unknown to me. Though this bug also must migrate with the 

 fading of the flowers, after the habit of Misumena, it is winged and 

 does not have to go "on foot" as the spider probably does. \\ 'hen dis- 

 turbed these bugs do not as a rule seek to escape by flight, and it is not 

 unlikely that they often crawl from one flower to another when the 

 distance is short. The soldier-beetle is similar to the ambush bug in 

 its propensity to copulate on flowers. The milkweed beetles and the 

 dogbane beetle are commonly seen copulating upon the leaves and 

 stems of the plants on which they live. The larva of the milkweed 

 beetles bore into the roots and stems of plants ; the dogbane beetle has 

 similar habits. Of the butterflies, Anosia was observed copulating on 

 the willows, one sex with the wings spread, the fore ones overlapping 

 in part the hinder pair, the other sex with the wings folded together 

 vertically, the heads of the insects being turned in opposite directions. 

 The eggs of the mosquito are laid near the surface of the water. The 

 honev-bee and bumblebees are social, and the breeding and care of 

 the young are quite different from those of the other animals found 

 in this habitat. Xylocopa cuts the nest for its brood in solid wood, 

 and seems rather foreign upon the prairie, although posts and ties 

 are now to be found there. The rusty digger-wasp provisions its nest, 

 which is dug in the ground, with various grasshoppers ; upon these the 

 egg is laid and the young larva feeds. This wasp probably did not 

 breed in this moist habitat. The wet substratum here is probably un- 

 favorable for the breeding of those Orthoptera which deposit their 

 eggs in the soil. 



