200 



wardly curved spine-like processes which are armed at apices with 

 several short thorns. 



The foregoing descriptions are made from a larva and pupa 

 bearing the Laboratory accession number 26281, obtained by Dr. S. A. 

 Forbes in Delavan Lake, Wis., May 25, 1892, taken in an inlet among 

 weeds at the surface, and one larva, accession number 26282, taken 

 hy the same collector at the same place May 26, 1892. 



The species is undoubtedly truly aquatic, judging from the struc- 

 ture of the apical segment. No means is at hand for associating the 

 early stages with any described imago. 



T1PUI.A sp. 2 



Larva (PI. XXVIII, Fig. 2). — Length, 45-55 mm. Brown, 

 without well-defined vittae (alcoholic specimens). 



General structure as in above-cited figure. The principal differ- 

 ences in head structure between this species and the preceding lie in 

 the shape of the labium and the hypopharynx, the former ( PI. XXXII, 

 Fig. 5) having a strongly produced central tooth and no distinct 

 laterals, while the latter (PI. XXXI, Fig. 13) has the anterior margin 

 with only 2 weak protuberances and no rounded teeth; frontal plate 

 as in Figure 9, Plate XXXI. Body without close pubescence, the 

 armature as shown in Figure 2, Plate XXVIII; abdominal segments 

 with the posterior lateral bristles on both dorsum and venter situated 

 on pseudopod-like elevations; apical segment as in Figure 3, Plate 

 XXVIIL 



The foregoing description was made from alcoholic specimens 

 in the Laboratory collection bearing the following data: Accession 

 number 25756, Urbana, May 7, 1888, taken in woods (C. A. Hart) ; 

 and two examples submitted by J. A. Hyslop (ace. 6687) from 

 Hagerstown, Md. 



TiPUivA sp. 2a 



This specimen may really be a young example of the foregoing, 

 as it differs only in size (20 mm.) and in having a process on each 

 side of the penultimate abdominal segment. 



Locality, Blacktail Deer Creek, Yellowstone National Park, 

 August 28, 1890; taken in an aquatic collection among vegetable 

 debris (S. A. Forbes). 



TiPULA ABDOMINAUS Say 

 Ctenophora abdominalis Say, Jour. Acad. Nat. Sci. Phila., Vol. 3, p. 18. (1823) 

 Tipula abdominalis Say, Needham, Bull. 47, N. Y. State Mus., p. 575. (1901) 



