OF WASHINGTON. 7 



SWARMING OF A REDUVIID. 



[Hemiptera-Heteroptera.] 

 By FREDERICK KNAB. 



The swarming of the males of nemocerous Diptera is a 

 common and familiar phenomenon but I am not aware that 

 such a habit has often been recorded for the Hemiptera. 

 Late on the afternoon of January 4, 1908, when collecting 

 in the outskirts of Cordoba, Mexico, I came upon a swarm of 

 small insects, to all appearances Nemocera. It was at the 

 intersection of two paths through the coffee groves, where 

 the sun shone in obliquely. The insects were dancing in 

 the sunlight in the open space in the manner of male Nemo- 

 cera. They all faced in the same direction, just as do the 

 Nemocera, in response to currents of air. The swarm con- 

 sisted of several hundred individuals, weaving up and down 

 among each other. When captured the insects proved to be 

 a very small species of Reduviidae. Mr. Heidemann has de- 

 termined the species as Henicocephalus culicis Uhler. A little 

 later, at 4:30 p. m., at another intersection of paths, another 

 swarm of the same insects was found, dancing in the sun- 

 light. The swarm was larger than the first one and the in- 

 sects moved more rapidly. When the sun disappeared behind 

 some trees, a short time after, the swarm dispersed. I have 

 not yet determined if the individuals in the swarm are all 

 males, as is the case with the Nemocera. 



Mr. Heidemann said that Henicocephalus (Enicocephalus') 

 was erected by Westwood in 1837, but has been described by 

 various other authors since then, under different names, on 

 account of differences in the head and thorax which are now 

 considered as only specific characters. The genus is cosmo- 

 politan, but specimens are not common. Twenty-five species 

 have been recorded. Six of these are from North America. 

 The genus was based on the species flauicollis from St. Vin- 

 cent, West Indies. He called attention to a note by Carlos 

 Berg in the Berliner Entomologische Zeitschrift, Volume 

 xxxvin, 1893, p. 362, entitled " Lebensweise von Henico- 



