1908] Fauna Ottawaensis. 71 



the cells opening downward, within the protecting oval coverings. 

 As the sinnmer draws to a close, larger cells are constructed and 

 males and perfect females are developed. After mating the 

 males graduallv perish, and the whole colony succumbs to cold 

 and starvation, with the exception of such females as may find 

 suitable hibernating quarters and survive to found new colonies 

 next year. Notwithstanding their fierce dispositions and 

 venomous stings, the wasps cannot protect their nests from 

 parasitic intruders. Forty years ago Mr. W. Couper, who then 

 resided in Ottawa, bred from a nest of V. maculata a tryphonid 

 which was sent by Mr. Billings to Mr. Cresson, who described 

 it in the Canadian Entomologist, Vol. I, page 104, under the 

 name Eticeros burnis. The species has been redescribed by 

 Rev. J. L. Zabriskic as Sphecophagtis (?) .predator, and more 

 recentlv has been referred to the genus Cacotropa by Mr. Davis. 

 Dr. Fletcher has found apparently the same species, though 

 varving somewhat in coloration, abundant in nests of V. diaboUca. 

 Polistes belongs also to the social wasps, but its colonies are small. 

 The nest consists of only one layer of cells, without any covering, 

 and is attached to the under side of a stone, or occasionally in 

 buildings or in some other sheltered situation. A nest recently 

 found (19th April, 1908), under a flat stone in a sandy field, 

 consists of 98 cells and was attached by a large central pedicel 

 and several small ones around the edge. Between the nest and 

 the stone a lively female wasp was found which had apparently 

 hibernated there and which might possibly have used the nest 

 again instead of starting a new one. 



The Eumenidce haA'e longitudinally folded wings like the 

 Vespidce, but are smaller wasps which are solitary in their habits 

 and are not paper-makers. All our species are black, w4th 

 yellowish or whitish markings, and are abundant at the end of 

 summer on Spiraea, golden rod, etc., in common with many of our 

 other wasps which may then be easily captured. Eumenes has 

 a petiolated abdomen and constructs of clay a curious little vase- 

 shaped nest attached to twigs. The cell is provisioned with 

 small caterpillars, of wdiich those called loopers or measuring- 

 worms seem to be preferred, and the egg is suspended from the 

 torj of the cell bv a slender thread so that it may not be crushed 

 bv the inoving about of the caterpillars. The rest of our 

 Eumenidge are included in the extensive genus Odynerus which 

 contains according to the Genera Insectorum 796 described 

 species. The twelve Ottawa species are divided equally between 

 the three subgenera Leionotus (Nos. 37-40), Ancistrocerus 

 (Nos. 41-44) and Symmorphus (Nos. 45-^8). Their nesting 

 habits are varied; some building clay cells under stones or in 



