JAPETUS Steenstrup's interest, as is well known, extended to almost all groups 

 within Zoology. Among the Arthropods he has given us works on Crustacea, 

 partly alone, partly together with Lutken; further he published in 1857 a note 

 about the species of Phytopius living on the Scandinavian trees and other 

 piants. On the other hånd there exists no work by Steenstrup on Insects ; it is 

 known however, that also that class had caught his interest. Most frequently it 

 was forms with specially interesting biology or in other ways peculiar, which 

 attracted Steenstrup's attention, and roused his desire to make a closer study. 

 So also concerning the Insects ; he had here fixed his attention on the pelagic 

 Hemipteres, a group which on account of its marine occurrence stands out so cha- 

 racteristic and isolated. For a time he thought of writing a monograph of these 

 animals together with Meinert, but this plan was never realized. 



No wonder that Steenstrup had thought of such a monograph, for he was in 

 possession of an exceedingly large material of those animals, belonging to the study 

 collection of the University of Copenhagen. As is well known Steenstrup had a whole 

 staff of collectors, especially sea-captains, whom he had managed to interest in a 

 very high degree in collecting work, and from whom he therefore received abundant 

 material from many different parts of the world. In reality Steenstrup in this 

 manner succeeded in procuring a material, especially of Plankton-forms, far sur- 

 passing that of any other museum at that time. Steenstrup also in his works 

 names several of the collectors with acknowledgments. It is again the same names 

 we meet associated with the material of Halobatids, especially A. F. Andrea and 

 V. Hygom. 



After the death of Steenstrup his material of Halohates came to the Depart- 

 ment of Arthropods of the Museum. Besides imagines and larvæ it contained also 

 a large collection of eggs of those animals ; this collection is of great interest, as 

 only very little is known of the eggs of Halobates. It is also to be seen that Steen- 

 strup had strongly fixed his attention upon the eggs; for together with his material 



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