Vol. xxii] ENTOMOLOGICAL NEWS. 459 



Explanation of Plates XVII-XIX. 

 (All three Plates refer to Mecistogaster modestus Selys). 



Plate XVII. 



Fig. I. Tarsus and distal end of tibia, larva No. 2. x 23- 



Fig. 2. A little more than the right half of distal margin of mentum, 

 dorsal surface, larva No. i. x 28. 



Fig. 3. Right antenna, larva No. i. x 18. 



Fig. 4. A single trifid spine from the proximal tarsal joint of fig. 

 1, length .07 mm. x 370. 



Fig. 5. Lateral labial lobe from exuvia of larva No. 49. x 14. 



Fig. 6. Labium, larva No. i. x 8. 



Fig. 7. Principal tracheae supplying the rectum, larva No. I. The 

 outlines of the ileum and rectum are shown by broken lines. The left 

 dorsal trachea (WO lias been turned to the left out of its normal 

 position. X 9. 



Fig. 8. Some of the principal viscera of larva No. i. The outline 

 of thorax and first seven abdominal segments has been shown on the 

 right side only, the dorsal body-wall being supposed to have been 

 entirely removed from these segments, but its right half retained and 

 spread out to the right in segments 8-10. The dorsal trachea is in 

 normal position on the right (rdt), but turned over out of position 

 (Idt), and the lateral trachea {lit) also exposed, on the left. The 

 dotted lines on the head show the outlines of the compound eyes, x 4^/2 . 



Fig. 9. One-fourth of the gizzard armature as seen when the viscus 

 is cut lengthwise and spread out flat, larva No. i. x 45. 



Fig. ID. Inner surface of the rectum, larva No. i, cut lengthwise 

 to the right of the mid-dorsal line and spread out flat, x 16. 



Fig. II. A caudal gill of larva No. loi. x 9. 



Fig. 12, 13. Caudal gills from larvae Nos. 48 or 49 and i, respec- 

 tively. X 9. 



All these figures drawn by camera lucida and compound microscope. 

 Abbreviations : 



ab, abductor muscle. 



ad, adductor muscle. 



br, brain (cerebral ganglia). 



dv, dorsal vessel. 



fg, fore gut. 



gj, seventh abd. ganglia 



il, ileum. 



Icgt, trachea to left caudal gill. 



Idt, left dorsal trachea. 



lit, left lateral trachea. 



Ivrt, left ventral rectal trachea. 



mcgt, trachea to median caudal 



gill. 

 mdrt, mid-dorsal rectal trachea. 

 mg, mid-gut. 

 nissp, mesostigma. 

 tnt, Malpighian tubules. 

 mtsp, metastigma. 

 og, optic ganglion. 

 r, rectum. 



rcgt, trachea to right caudal gill. 

 rdt, right dorsal trachea. 



