5O8 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE . 
Cyclorrhapha include a paper by Banks (19) and the papers by 
Greene (207, 202) on the puparia and larvae of muscoid flies. The 
aquatic Diptera have been studied by Johannsen (255, 255a), and his 
papers are of great value. 
Obviously, any key for the identification of dipterous larvae, even 
as to family, must necessarily be highly technical and of little prac- 
tical use for those other than the specialist. Since the present work 
is for the use of those less expert, it is believed that some of the more 
common species may be sufficiently identified by the character of their 
_ injury or by their habits. With this in mind the Diptera herein may 
be conveniently grouped as follows: 
Is Phytophagous Species fa as ae Se pe ee p. 508 
II. Nonphytophagous species 
Ap Bloodysicking Species 3 22 Ba See ene Eee Seer ae ee p. 526 
B. MG OParasiticys Pe Cres eu see eee eee rere eee yee p. 530 
a. Endoparasites of mammals (injurious species)___________ p. 530 
b. Endoparasites of various injurious species (largely bene- 
fievenl)) <2 25s SSS Sh eee aR SN er ee ee eae p. 531 
C,. -Predaceous species &. = ee eee) See eel ea ys ee eee p. 533 
D. Species chiefly scavengers, or fungivorous_______________-____ p. 536 
PHYTOPHAGOUS SPECIES 
Character of injury and the families commonly concerned : 
Gall makers Fruit- and seed-infesting species 
Itonididae Itonididae 
Argomyzidae Trypeditae 
Tephritidae Chloropidae 
Leaf miners Root feeders 
Itonididae Tripulidae 
Agromyzidae Anthomyiidae 
Cambium miners 
Agromy zidae 
KEY TO FAMILIES OF PHYTOPHAGOUS SPECIES 
LARVAE 
1. Larva with a sclerotized structure called “breastbone”’ near the 
anteriorcend as sw i ee eee caret eee ce ghee Itonididae p. 509. 
Larva not.characterized: as abOvels 55.) was lee ene 2 
2. Head complete, or the posterior portion with deep longitudinal 
incision; mandibles moving horizontally_______- Tipulidae p. 524. 
Head incomplete, without a strongly developed upper arcuate 
plate; mandibles moving verjuicallliy eee eee 3 
By Large larva (9-12 mm.); body tapering or broadly rounded poster- 
iorly; posterior spiracular plate: with 3: slits see et eee ay 
Small larva (8-4 mm.); posterior segment rarely truneate or with 
tubercles; posterior spiracular plate usually with more than 3 
spiracular openings (if otherwise characterized see Chloropidae, 
| Oh 45) en ne an ence ees cg ee ee TE ea) Argomyzidae p. 521. 
Slender larva, ranging from 11 to 30 mm. in length with an average 
diameter of 1 mm. or less (cambium miners) Agromyzidae, p. 522. 
4. Posterior segment with 4 distinct tubercles in a transverse row 
below the spiracular plates; anterior spiracles with about 6 
lobess@Hylem7ya)\e eo ae ee eee ee Anthomyiidae, p. 537. 
Posterior segment with or without tubercles, if present, not ar- 
ranged as above; anterior spiracles usually with 10 or more lobes 
I. ANMITLe PUL are O Wes ee ee ee Tephritidae p. 524. 
