204 SEVENTEENTH Report STATE ENTOMOLOGIST oF MINNESOTA—1918 
sites (Psyche, May 1894). Walsh has bred Chrysis caerulans from the 
potter wasp. The species are small, but conspicuous on account of 
their brilliant coloration, generally metallic green or blue. They 
run or fly rapidly in the hot sunshine and in England have been 
given the name of “cuckoo flies,’’ because of their resemblance in habits 
to the European cuckoo, 1n that they steal into the nests of fossorial 
wasps or bees, as the cuckoo does with other birds, when the owner is 
away, and lay eggs therein. They are most persistent parasites and an 
incident is on record where an enraged wasp returning to her nest and 
finding a “cuckoo fly” on the point of leaving her egg there, attacked 
the latter, and being unable to sting her because Chrysidids double 
themselves up and present only an armoured surface, gnawed off the 
parasite’s wings and threw her out on the ground. The unwelcome 
and disabled parasite however, after the departure of the rightful 
owner, crawled up the post and into the nest wounded as she was, and 
deposited her egg before dying. 
CHRYSIDEDAE. 
With the characteristics of the sub-order 
The insects of this family are often called ‘cuckoo flies” or “gold 
wasps.” 
The only family in the suborder and hence partakes of all the 
characteristics given above. The species are well distributed over most 
parts of the world. While a few forms attain a length of ™% inch or 
more, they are for the most part small insects. Their bodies are strik- 
ingly stout. The abdomen of some species is tipped with red. The 
sting has no poison sack and is at the end of a retractile tube consist- 
ing of the posterior abdominal segments. There are over 400 known 
species which are guests or parasites in the nests of bees and wasps. 
Chrysislauta, C. (Tetrachrysis) caerulans F. (see colored plate 1). 
C. (Tetrachrysis) nitidula F. C. (Oleochrysis) pacifica Say, and 
FHedychrum sp. occur in Minnesota. Tetrachrysis sp. taken in Mar- 
tin County on Aster in September. 
VESPOIDEA 
Wings usually well developed, sometimes vestigeal or lost; body not flea-like; 
wings usually with venation well developed; trochanters composed of one joint: 
cutting edge of mandibles turned inward, their tips meeting or overlapping when 
mandibles are flexed toward mouth. 
This familiar group contains, besides some parasites, our social 
wasps, strictly predaceous and insectivorous. They feed their young 
