Xylophagidae. 79 



at Silkeborg. My dates are ^■•k—"k. The larvæ have been taken in 

 Ermelund, Dyrehaven and Bollemosen in beech on " h and ^■^/ll and 

 again on '**/3— Vn. 



Geographical distribution: — Northern and niiddle Europe from 

 Lapland to northern France. Zetterstedt remarks that in southern 

 Sweden he always found tlie larvæ in poplar. but in the northern parts 

 always in birch. 



2. Xylomyia Rond. 



(Suhiila Meig.) 



Species of middle size and of black colour, often with yellow 

 designs. Head short, broader than high, as broad as thorax, flat behind. 

 Yowls very narrow, only forming an upwards bent margin along the 

 inner eye-margin; epistoma small, retreating. Antennæ inserted below 

 the middle of the head, elongated, fusiform, ten-jointed; the two basal 

 joints of nearly equal length ; the others forming an annulated complex, 

 the first joint of which is longer than the follovving, the complex termi- 

 nating in a short and thin style. Eyes bare, equally separated in both 

 sexes. Front and vertex slightly depressed. The membranous part 

 around the mouth edge is small , and thus no real oral cone is 

 formed; clypeus partly membranous, proboscis short, labrum semi- 

 tubular, as long as labium ; hypopharynx a little shorter, somewhat 

 triangular; the maxillæ have a short lacinia and two-jointed palpi ; in 

 the female the second joint is somewhat thickened and pointed, in the 

 male it is smaller. The labella are broad, protruding forwards. Thorax 

 is longer than broad. Abdomen elongated, a little flattened, broadest 

 at the middle; it consists of seven segments; the last segment is in 

 the male small, often hidden. Genitalia in the male consisting of a 

 broad median apparatus, and some complicated lateral appendages; 

 in the female the abdomen terminales in two small lameilæ. Wings 

 (Fig. 29) with the cubital vein forked; between the discai cell and the 

 postical vein a postical cross-vein; the third of the veins rising from 

 the discai cell unites near the apex with the postical vein ; thus there 

 are five poslerior cells of which the fourth is closed. 



The larvæ highly resemble those of some Stratiomyids, as f. inst. 

 Sargus. They are broad, with parallel sides, of brown colour; the 

 head is broadly conical and resembles in structure and with regard 

 to the moutli parts the head of the larvæ of Stratiomyids. The body 

 consists of twelve segments in all; the segments are broader than long, 

 the last segment semicircular. The segments bear on each surface 

 some long bristles in a transverse row. especially there are on the 



