582 GEOLOGICAL SURVEY OF THE TERRITORIES 
EXPLANATION OF PLATE XXXIV. 
Fig. 1. Streptocephalus texanus Pack. Third developmental stage, dorsal view. Length 
0.2mm, 0c, ocellus; md, mandibles; mdp, mandibular palpus; sg, shell gland; 
m, transverse muscle of the 2d antennz; m, levator muscle of the labrum; 
m*, rectal muscles; int, intestines; s!, forked spine on 2d joint of 2d anten- 
ne. 
Fie. la. Union of the two muscles m! in Fig. 1. 
Fig. 2. 2d antenne seen from below. Larva 4.2™™ in length. ° 
Fig. 3. Ist antenne, 3d larval stage; n, antennal nerve; mnc, marginal nerve-cells; 
sp. ¢, bipolar spindle-shaped cells; s, sete. 
Fig. 4. Ist antenne of larva when 3™™ in length; lettering as in Fig. 3; gc, terminal 
ganglion cells. 
Fig. 5. 2d antennee of larva 4™™ in length; s1, s?, spines of basal joints. 
Fic. 6. Mouthparts of same larva as Fig. 5, and drawn to the same proportions; md, 
mandible; mp, mandibular palpus; ma!, Ist maxilla; m!p, ist maxillary 
palpus; mx?, 2d maxilla. 
Fig. 7. The maxille (1st and 2d) of larva when 5™™ in length. 
Fig. 8. Chirocephalus holmani Ryder (Glendale, L. I.), tip of Ist antennsz and olfactory 
seta. 
Fic. 9. Mouth of larva of S. teranus when 5™™ in length. 
Fic. 10. Branchipus vernalis Verrill. Olfactory seta. 
Fig. 11. Chirocephalus holmani Ryder. Dorsal bristle of 3d segment, a little way from 
the articulation; Fig. 1la, the same on the 2d (genital) segment. 
Note.—All the figures in this plate were drawn by C. F. Gissler, Ph. D. 
