149 



interest. The catalogue numbers — 591 in 1908, 771 in 1909, 718- 

 in 1 910, and 969 in 1 911— large as they are, give a very inadequate 

 idea of the material ; for the catalogue is of mounts rather than 

 specimens, of which many are constantly carried on a single card. 

 The collection includes many specimens captured and presented 

 by Mr. Hamm's son, Mr. C. H. Hamm. 



" A part of the results has been already published in the En- 

 tomologist's Monthly Magazine for 1908, p. 181, and 1909, pp. 132 

 and 157 ; but the most novel and interesting observations and 

 conclusions — those obtained with the genus Hilara — are made 

 known for the first time in the following brief account of Mr. 

 Hamm's gift. The full and detailed account awaits publication 

 until numbers of obscure and minute insects — Dipterous captors 

 and prey chiefly Dipterous — have been satisfactorily worked out. 



" The collection has been classified by Mr. Hamm so as to illus- 

 trate his conclusions, the species being arranged in groups, each 

 representing a definite evolutionary stage in the use of prey — 

 first and lowest as food devoured by both sexes without relation 

 to pairing ; then as a gift provided by the male and devoured by 

 the female during pairing ; finally, as it were an ornament or 

 plaything — no longer eaten by the female, but acting as a lure 

 and a stimulus. In this last stage the prey is often replaced 

 by some vegetable fragment which is quite unsuitable as food. 

 The climax of this line of evolution is reached in an elaborate 

 cocoon spun by the male around the prey and replacing the latter 

 as an object of attraction. This replacement is self-evident in 

 many examples studied by Mr. Hamm ; for in these there was 

 nothing but an empty cocoon, the prey having probably been 

 lost during the process of construction. 



"There are strong reasons for the belief that the last stage 

 has been reached through the second and the second through 

 the first, but this inference must not be extended further and 

 made to apply to the species themselves. 



"émpido and their prey IX RELATION TO (OURTSIIIP. 



" I. Prey devoured by both sexes independently of pairing. 



" [a) Tachydvomia [Tachydroinincc). — Prey very nearly always 

 Dipterous and often belonging to the genus Tachydromia, per- 

 haps sometimes to the same species as the captor. The female 



