1888.) 77 



DESCRIPTION OP THE ASH-CAULIFLOWER GNAT. 



BY R. H. MEADE. 



DlPLOSIS FRAXHSTELLA, Sp. n. 



Cecidomyia minuta ?, Winnertz. 



Flava, thorace nigro-striato ; abdomine basi-nigro; halteribus albis,amplisque; 

 alts, venis cubitalibus prope apicibus eoceuntibus. Long. £ et ? § mm. 



Head black ; palpi and proboscis pale yellow ; face with a tuft of white bairs ; 

 antennae in male about one and a half times the length of the insect, consisting of 

 2 basal joints which are yellow and sessile, and of 24 moniliform pedicelled ones, of 

 a pale brown colour, verticellated with white hairs ; the stalks are about as long as 

 the joints : in the female the antennae are nearly as long as the body without the 

 oviduct, and consist of 2 basal joints as in the male, and of 12 ovoid very shortly 

 pedicelled others, to which a minute, tapering, terminal one is added. 



Thorax brownish-yellow, marked with three longitudinal brownish-black stripes, 

 which are almost confluent in the male, so that the dorsum looks nearly black ; 

 in the female the middle stripe is broad, while the lateral ones are very narrow. 



Abdomen yellow, clothed with white hairs, and having the base blackened ; the 

 black part is more distinct in the female than in the male, especially upon the upper- 

 surface ; forceps of male large and yellow ; oviduct of female wanting.* 



Halteres large and white. 



Wings clothed with dark hairs ; second longitudinal or cubital vein almost 

 straight until it nears the extremity, when it curves rather suddenly down ; and 

 reaches the border apparently slightly before the apex ; anal vein very indistinct. 



Legs with trochanters very pale, the other joints are clothed upon their upper- 

 sides with black hairs, which are most numerous upon the tarsi, which look darker 

 than the rest of the legs; the under-surfaces are furnished with white hairs, so that 

 the legs look white beneath. 



This very minute Cecid is probably the same as the one described 

 by Winnertz under the name of G. minuta. It is rather an anomalous 

 species, for though the antennae are fully characteristic of the genus 

 Diplosis, Lw., the direction of the cubital vein more resembles that of 

 Cecidomyia, the point terminating apparently a little before the apex 

 of the wing. Winnertz only knew the male of his G minuta, and was 

 ignorant of its life-history ; it also differed according to his descrip- 

 tion from the male of the ash-gall Diplosis, by having the antennae 

 twice as long as the body, and the points of the forceps black; I have, 

 therefore, thought it better to describe it as a new species, giving it a 

 characteristic name. 



Like some other species of Diplosis this one lives as an inquiline 

 in the cauliflower, ash-gall, where it was found by Dr. Chapman, in 

 August, 1887, along with the larvae of Frays rustica, and was kindly 

 sent by him to me for identification. 



Bradford, Yorks : August, 1888. 



* The only two specimens which I received were dried, in which state the male organs 

 cannot be fully described. 



