368 Phylum. Arthropoda 



Hibernation presents no problem in Pieris, Euchloe, and other butter- 

 flies which winter as chrysalids. It is more difficult in Colias spp., which 

 usually hibernate as half grown caterpillars. Loss of moisture and 

 haemolymph by the chrysalids of these species during the winter usually 

 prevents eclosion in the spring; the wings cannot expand. 



The natural method of hibernation, burying the caterpillars deeply in 

 moist, sandy soil, sometimes succeeds, if they are placed in boxes or tins 

 inverted so that moisture will not collect, and packed in a bushel or more 

 of excelsior; but even in a cool, well-shaded excavation they may be 

 killed by molds in early spring before clover in the fields begins to grow. 

 An electric refrigerator, with atmosphere well humidified, is far more 

 likely to give dependable results. 



Order Diptera 

 Superfamily tipuloidea 



CRANEFLIES 



J. Speed Rogers, University of Florida 



APPROXIMATELY 700 to 800 species of craneflies, distributed among 

 l 4 families* and about 120 genera and subgenera are known from 

 North America. Many of the species are rare, restricted in distribution, 

 or little known, but a large number are common and widely distributed. 

 They often form a considerable element of the insect fauna of stream- 

 courses, swamps, marshes, woods, and grasslands where their larvae occur 

 in a wide variety of aquatic, semi-aquatic, wet, or moist situations. In- 

 deed, along the shaded banks of upland rills and seepage areas and on 

 wet, mossy cliffs craneflies are frequently the dominant forms of insect 

 life. 



A partial knowledge of the life histories and immature stages of repre- 

 sentative species of each of the families and subfamilies and of more 

 than % of all the genera has been obtained; but the life histories of 

 more than % of the species are wholly unknown, and few of the others 

 have been carried through a complete life cycle within the breeding cage. 

 The following discussion of rearing and culturing methods is thus limited 

 and conditioned by a very incomplete knowledge of the life histories of a 

 large majority of the species. 



For the purpose of rearing adults or maintaining cultures, craneflies 

 may be divided into five broad and overlapping groups: 



♦Tanyderidae, i genus, 3 species; Ptychopteridae, 3 genera, 7 species; Trichoceridae, 

 3 genera, about 12 species; Tipulidae, 3 subfamilies, some no to 115 genera and sub- 

 genera and more than 700 species. 



