158 Psyche [October 



readily on small maggots, such as are found under decaying bark. 

 Two larvae were preserved in alcohol, as were a few pupae. The 

 rest were allowed to pupate and emerge. All larval and pupal 

 exuviae were preserved. It is from this material that I have made 

 the observations recorded in this paper. 



At this time, I wish to extend my sincere thanks to Dr. George 

 Dimmock of Springfield for valuable aid and suggestions, to the 

 staff of the Osborn Zoological Laboratory, Yale University, for the 

 use of laboratory instruments and facilities, and to Mr. Herbert 

 S. Barber of the National Museum, for identification of the species. 



Larva of Xantholinus cephalus 



Form depressed slender fusiform, with ventral side of body straight, fitted for 

 locomotion on flat surfaces, eight and one-half times longer than wide, head and 

 thoracic segments nearly equal in width, greatest width at foiu-th abdominal seg- 

 ment. Length of mature larva, 9.5 mm. Head quadrate, depressed, sides nearly 

 parallel. Neck five-eighths width of head, vnih. a V shaped indentation on ventral 

 posterior margin. Episfoma pentagonal, reaching posteriorly about one-third dis- 

 tance from anterior margin of clypeus to posterior margin of head, with V shaped 

 indentation in lateral margins, with a large seta slightly posterior to apex of inden- 

 tation. Other setfe symmetrically arranged. Frontal angles not prominent. 

 Clypeus not separate from epistoma, dentate on anterior margin, one tooth at middle 

 and four teeth on either side, the first tooth from the middle being the largest. 

 Numerous large setaj symmetrically arranged. Hypostoma somewhat pentagonal, 

 about one-half length of head. Four setse arranged along lateral margins. Horn on 

 each anterior angle, directed forward, one seta at base of each horn. Ocelli minute, 

 probably four, confluent. Not apparent in shed larval skins. Antennce four 

 jointed, slightly longer than mandibles; first joint nearly hemispherical, nearly as 

 wide as long, no setae. Second joint clavate cylindrical, one-fifth as wide as long 

 and four times as long as the first, with a single seta situated near the base on the 

 external dorsal side. Third joint fusiform four times longer than wide and four- 

 fifths as long as the second, outer ventral angle obliquely truncated and bearing on 

 the truncation a prominent acorn shaped appendLx, five setse situated on the upper 

 half of the third joint. Fourth joint slender, somewhat clavate, bearing three large 

 and four small setae on its tip. Antennal formula: .05 .21 .17 (.03) .10. 

 Mandibles three times longer than wide, toothless, slender acuminate falciform, 

 three setse on outer margin, a small one near the base, a large one the same distance 

 in advance, and a third, small, slightly less than half way between base and apex. 

 Maxillae equal in length to antennae. Maxillary stipes slightly less than half length 

 of mandible, subcylindrical, five times longer than wide, apex obliquely truncated 

 on inside, with four setae on outside ^nd two on inside along margins. Outer lobe 

 seven-ninths as long as first joint of palp, a single slender, conical joint four times 

 longer than wide, with a single stout seta at apex. Inner lobe lacking. Palpigerous 

 stipes stout, cylindrical, two-thirds as wide as long, unadorned. Maxillary palp 



