160 THE CANADIAN ENTOMOLOGIbT. 



metallic golden-green, flies, which appear, as Verrall said, "to be 

 standing on tiptoe," being raised on their front legs. Their wing 

 venation is very characteristic. The most remarkable thing about 

 the family, however, is the sexual dimorphism of the male, which 

 reaches a higher degree of development in this family than in any 

 of the other family of the Diptera. These secondary sexual 

 characters occur primarily on the legs, but they are also found on 

 wings, antenna; and facial region. Associated, as is usually the 

 case, with these secondary sexual characters in the male Doli- 

 chopodidsare remarkable "courting" habits, which not infrequently 

 strongly recall the analogous amatory preliminaries on higher 

 animals. The flies are all predaceous, feeding on other insects and 

 small invertebrates, and are usually found on bushes, on low 

 herbage and grass in woods and outside, generally in damp locali- 

 ties and more or less near water. In North America we have little 

 information as to their life-histories; the larvae occur in earth rich 

 in vegetation and under the bark of trees. The species are dis- 

 tributed all over the world, two species of Dolichopiis being found 

 in Greenland. From North America about 526 species are known, 

 from the palsearctic region about 586 species are known, and ten 

 species are recorded as common to both regions. 



Aldrich divides the family in North America into twelve sub- 

 families, and although the former worker has given no diagnoses, 

 the author of the present work believes them to be good and 

 natural. As he has only examined the Danish species closely, he 

 follows the arrangement of the "Katalog der Palaarktischen 

 Diptera," and divides the family into four subfamilies, at the same 

 time admitting the heterogeneous nature of some of them. 



As in the previous parts of this excellent work, the author 

 treats each species fully; where they are known, larval character- 

 istics and habits are given, and the presence of one hundred and 

 thirty figures, chiefly of the antennae and wings, enhances the value 

 of this further and most welcome addition to our dipterological 

 literature. We look forward to the succeeding parts of this 

 monumental work, in the preparation of which the author has our 

 good wishes. 



C. G. H. 



Mailed May 17th, 1813. 



