12 CYRTIDAE OF NORTH AMERICA 



A pair was observed in copulation, the male bracing itself with 

 its hind legs on the costal border of the long wings of the female. 



Westwood, Van Heyden and M. V. Auduoin all observed 

 that a certain species of Crabro invariably selected Ogcodes gih- 

 hosus to store its burrows in the brambles. Rev. H. S. Gorham 

 observed this same thing; he noticed a thistle (Cnicus palustris) 

 with a hole in it about three feet from the ground, around which 

 several spiders seemed watching. On investigating he found the 

 hollow stem which led to the hole filled for about eight inches 

 with the rare fly Ogcodes gihbo.ms. There were twenty-five or 

 thirty flies, then a wad of frass or debris, and then another seg- 

 ment and a wad. In some a hymenopterous larva was engaged 

 in devouring the stored-up flies. The spiders remarkably re- 

 sembled the Cyrtids and Dr. Sharp pointed out that they were 

 undoubtedly hosts of the flies; the mimicry never having been 

 noticed before. In all more than fifty flies were found in the 

 burrows, dead but cjuite fresh. Another Cyrtid, Helle longir- 

 ostris Hudson, from Australia, is "an extraordinary and very 

 rare species, occurring among white rata {Metrosideros scandens) 

 blossoms in February." 



The Cyrtidae are very clumsy and sluggish when walking, 

 some of them falling over easily. Pterodontia is described as hav- 

 ing a balloon-like flight. Opsehius diligens has a floating sort of 

 flight, rather undulating and uncertain. It has the habit of 

 buzzing around in circles when it falls over on its back on a 

 smooth surface, often doing this for some time before it can 

 regain its feet; most of the time it is making a high, thin humming 

 sound. When walking the long wings drag on the ground. I 

 collected a number of specimens in Southern California on warm 

 sunny days, flying around vines which contained spider's webs. 

 They seemed to have no fear of anything and could be easily 

 approached. They differ in this respect from EuloncJms tristis 

 and E. sapphirinus, both of which are quite wary, especially in 

 the heat of the day. The species of Eulonchus are very quick of 

 wing and are not sluggish when captured, although they are a 

 little clumsy. When caught in the net they hum like a Syrphid, 

 but make no noise when flying. Several specimens were taken 

 near Parkdale, Oregon, and were kept ahve for a short time, but 

 none Hved longer than forty hours and the females did not lay 



