THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. O 



floating in water near Havana, Illinois; the second was taken with 

 dip net and sieve from mud at bottom of the Illinois River at Havana; 

 the third from earth in bottom land in the same vicinity. From 

 the great abundance of adults at edge of water on mud in Idaho, I 

 had long supposed that the larvae must breed in rich, wet earth; if 

 there had been any truly aquatic forms there I must have seen them. 



The larvae are maggot-like, with eleven segments behind the poorly 

 developed head, of which five or six bear fleshy protuberances for 

 locomotion on the under side, provided with hooks, but imperfectly 

 paired, end of abdomen with two upper and two lower lobes, the 

 small posterior spiracles on the upper; anterior pair of spiracles very 

 minute. The head is of peculiar reduced structure, with vertical 

 hooks inside an open chitinous frame. The classical description is 

 of DolicJiopus ungulatus (as aeneus) by Brauer.^ This larva was 

 found in decomposing wood inside a hollow tree. 



The adults, as already remarked, are most abundant at the edge of 

 water on mud; some species, however, are regularly found on foliage 

 in half-shady places. Few are ever found in dry localities. They 

 are very local, and even those species which have been collected in a 

 dozen States are only to be found in just the right situation with 

 regard to sunlight, moisture, and vegetation; a few feet away the 

 search may be vain. 



The species are most numerous in decidedly cold regions, either far 

 north or in high altitudes southward. Two species are recorded from 

 Mexico, myosota from Northern Sonora and hifradus from Mexico 

 City, the latter being so far the extreme southern record for the genus 

 (old South American and Mexican references always turning out to 

 belong to species of other genera). A few species have been found 

 in the northern (palaearctic) edge of Africa, probably none south of 

 the thirtieth parallel, the latitude of New Orleans. 



The Catalogue of Palaearctic Diptera, 1903, lists 119 species in the 

 Old World, almost all from Europe. Siberia has hardly been touched 

 yet, but is undoubtedly very rich in this genus. The present paper 

 recognizes no fewer than 219 species and varieties from North Amer- 

 ica — a total of nearly 338 species and varieties thus far known (only 

 a few forms are regarded as varieties). 



It might be doubted whether such a vast number could properly 

 be classified as belonging to the same genus. The fact is that every 

 attempt at a division has been completely unsuccessful. Loew sepa- 

 rated Hygroceleuthus on the length of the face, which turns out to be 

 a male character occurring in some species otherwise quite far apart; 

 although Lundbeck retained this in his monograph he admitted that 

 it has slight value. Bigot proposed Spathichira for the species with 



5 Denkschr. Kais. Akad. Wiss., Vienna, vol. 47, 1882, pp. 29, 30, 44, pi. 4, figs. 72-75. 



