1913.] 179 



C. Empis trigramma, punctata aud scutellata (Empinds). A little 

 group of related species with habits very different from those of the 

 rest of the genus so far as it has been studied. 1909 — sixty-three. 



II. — The prey provided by the male is devoured or sucked 



BY the female during COPULATION. 



A. Pachymeria {Emphice). The prey always Dipterous. 1908 — 

 one hundred and ten ; 1909— one hundred and seventy-eight. 



B. Bliamphomyia (Empince). The prey nearly always Dipterous. 

 1909— three ; 1910— two hundred and fifty ; 1911— sixty -five. 



C. Empis (Empinx). Small species as yet undetermined. Prey 

 nearly always minute Diptera, chiefly Cecidomyia and Psychodes. 

 1909 -two ; 1910— fifty-five ; 1911— one hundred and three. 



D. Empis tessellata. Prey very varied, but always Dipterous. 

 1908— two ; 1909— two hundred and twenty-four ; 1910— twelve ; 

 1911— thirty-three. 



E. Empis opaca. Prey like that of tessellata, but mainly of the 

 genus Bibio. 1909 — one hundred and sixty-eight ; 1910— forty-six ; 

 1911— forty. 



F. Empis livida. Prey more varied than that of any other 

 species of the genus, but still chiefly Dipterous. 1908 — thi-ee hundred 

 and five, of which 4 were collected by Mr. C. H. Hamm ; 1909 — forty- 

 five ; 1911 — thirty-two. 



III. — The prey or object provided by the male is not de- 

 voured BY THE FEMALE, BUT BECOMES, AS IT WERE, AN 

 ORNAMENT OB PLAYTHING PROVIDING SOME INDISPENSABLE 

 STIMULUS. 



A. Hilara (Empinse). Many species as yet undetermined. All 

 the species fly over water, and the prey or other object is always 

 picked up from its surface by the male Hilara. The males take 

 floating insects of aU kinds - sometimes specially Diptera, sometimes 

 Aphids — scales off overhanging trees or other fragments of plants. 

 Some of the species will accept almost any floating object, while others 

 seem to restrict themselves to particular insects, such as Apliidx. 

 When the object is very heavy, the male, after seizing it, spins round 

 with great velocity till the load rises on a cone of water, and is finally 

 lifted from the apex. In Mr. Hamm's experiments, disabled Diptera 

 of the genus Chironomus, &c., stamens of buttercups, and ray florets 

 of daisies strewn on the water were soon taken by the males, and after- 

 wards found in the possession of the females. Pairing invariably 



