Mar., 1908.J Brues : Mutation Among Insects. 45 



A NEW CYNIPID FROM ARIZONA. 



By William Beutenmuller, 



New York City. 

 (Plate II.) 

 Aulax chrysothamni, new species 



Male and Female. — Head rufous, vertex piceous in the female, wholly black in 

 the male, very finely and minutely punctate. Antennae rufous in the female, piceous 

 in the male. Thorax black, very minutely and evenly punctate, subopaque ; parasidal 

 grooves obliterated anteriorly, very fine posteriorly and convergent at the scutellum. 

 Anterior lines from the collar very indistinct and scarcely reaching the middle of the 

 thorax. Median groove from the scutellum wanting. Pleurae finely striate. Scutel- 

 lum black, rugose, with two pit-like depressions at the base. Abdomen black in both 

 sexes. Legs rufous. Wings hyaline, with dark brown veins. Length of male 1. 50 

 mm. ; of the female 2 to 2.50 mm. 



Gall. — Polythalamous. White, densely covered with white felt-like substance. 

 Elongated, rounded or club-shaped, enlargements of the terminal twigs of the 

 branches of a species of Chrysothamnus (Bigelovia), measuring from 15 to 30 mm. 

 in length and 1 2 to 20 mm. in diameter. Sometimes two or three galls are in a row 

 on the same branch. Internally the gall is white and of a pithy substance. 



Habitat. — Tucson, Arizona (Gneomar von Krockow). 



IS MUTATION A FACTOR IN THE PRODUCTION 

 OF VESTIGIAL WINGS AMONG INSECTS?* 



By Charles T. Brues, 

 Milwaukee, Wis. 



The application by zoologists of experimental methods to the 

 investigation of the varied problems of evolution has become so general 

 during the past few years, that entomologists have almost entirely neg- 

 lected to search in any other way for facts bearing on the mutation 

 theory of De Vries. 



The wealth of insect species and the constancy of their specific 

 characters render them more available for non -experimental work of 

 this sort than probably any other group of living organisms. 



It is with the hope of calling attention to this interesting field that 

 I have been tempted to present the following scattered observations on 



*A paper read at the meeting of the Entomological Society of America at 

 Chicago, December 30, 1907. 



