233 



gall are conspicuous. They may be tinged with red ; when dry they 

 become brownish. 



ICHNEUMONIDiE 



Thalessa lunator Fabr. Lunate Long-sting. 



A female ichneumon of this species was found on a tree trunk in 

 the open glade in the lowland forest (Sta. IV, c) Aug. 22 (No. 143). 



The larva feeds, as an external parasite, upon, the larva of the 

 horntail, Tremex columha, which was also found in the Bates woods 

 (Sta. IV). I found T. lunator, both males and females, abundant 

 on shade trees at Bloomington, 111., October i, 1892, and also took it 

 July 26, 1895. Riley ('88) gives an excellent account of this species 

 accompanied by figures of the immature stages, and that of its host 

 as well. 



Tragus obsidianator Brulle. 



This black ichneumon with fulvous antennae was taken in the 

 Bates woods (Sta. IV) June 28, 191 1, by T. L. Hankinson (No. 

 7678). This wasp is known to be parasitic upon the larva of Papilio 

 polygenes Fabr. (P. asterias — Insect Life, Vol. i, p. 161) and 

 upon the caterpillar of Pyrrharctia Isabella ( ?) . This species has been 

 taken in central Illinois during June and July (Weed, Psyche, Vol. 5, p. 

 52). (See also Riley, in Amer. Ent., Vol. 3, p. 134. 1880.) 



Pelecinidje 



Pelecinus polyturator Drury. Black Longtail. (PI. LXIII, fig. 2.) 



This remarkable looking insect was found in the glade of the 

 lowland forest (Sta. IV, c) Aug. 20 (No. 117) and Aug. 22 (No. 

 143). Other females were seen in this forest. 



I have also' taken this species at Bloomington, 111. At Evanston, 

 111., during July, 191 o, this species was very abundant upon some 

 damp lawns. I have counted four or five females in sight at once. 

 They were often found upon blue-grass sod. The male of this 

 species is considered very rare. The only one which I ever captured 

 was taken July 29, 19 10, at Evanston, 111. The larva is parasitic 

 upon the grub of the May-beetle, Lachnosterna (Forbes, Eighteenth 

 Rep. State Ent. 111., p. 124. 1894). It may also prey upon other 

 scarabseid larvae inhabiting woodlands. 



FORMICIDiE 



Stigmatomma pallipes Hald. Old-fashioned Ant. 



A single wingless queen and four pupae (No. 140) were taken 

 Aug. 22 near the base of a ravine slope (Sta. IV, fc) in dense shaded 



