190 



Zoology of Colorado 



Harris is spherical, spiny, not very 

 large, but there are usually several 

 together. R. variabilis Bassett pro- 

 duces rather small smooth rounded 

 galls, more or less in a cluster. It 

 is interesting to gather these galls, 

 and those from the oaks, very 

 early in the year, anr' .see the in- 

 sects emerge in spring and early 

 summer. The observer will ob- 

 tain not only the true gall insects, 

 but many parasitic species, some of them metallic green. These 

 green parasites belong to the Callimomidae of the Chalcidoidea. 

 The females have long ovipositors. An exceptional member of 

 the Cynipidae is Ay lax pisum Walsh, which forms pea-like stem 

 galls on Lygodesmia, one of the Compositae. It may be found in 

 the vicinity of Denver. 



Galls of Rhodites rosaefolii CHI. on rose. 

 Evelyn Moore del. 



Ants (Formicoidea) 



The Colorado ants are placed in four families, but two of 

 these are sparingly represented. The pedicel or basal part of 

 the abdomen has two nodes or specialized segments in the Myrmi- 

 cidae, but in the other families there is only one such segment. 

 Only one of the latter (Poneridae) has the sting developed; the 

 Formicidae and Dolichoderidae are incapable of stinging. Our 

 Poneridae are very small, slow moving ants, and their nests are 

 not at all populous. The modified segment at the base of the 

 abdomen is obtuse or truncate above, seen in side view. Wheeler 

 took one specimen of the yellowish-red Ponera inexorata Wheeler 

 near Colorado Springs, and P. opaciceps Mayr is occasionally 

 found on the hill west of Boulder. A much larger member of this 

 family (Euponera hendersoni Cockerell) is fossil at Florissant. 

 The Dolichoderidae are also represented in our fauna by small 

 ants, but some of them are common. Tapinoma sessile Say is 

 known by the small size, dark color, and the scale or node of the 

 abdominal pedicel hardly developed. It also has a peculiar and 

 distinctive odor, something like that of rancid butter. Dory- 

 myrmex pyramicus variety niger Pergande is another small dark 



