1909] Homologies of Wing Veins 129 



PLATE XIX. 



Fig. 24. Chermes abietis (Linn.). Tracheation. Note how the branches 

 of the radial trachea weave along the margin. See page 110. 



Fig. 2.5. Chcrmcs abietis (Linn.). Tracheation. An extraordinary case 

 in which the first anal trachea is distinct to the base of the wing. See page 107. 



Fig. 26. Chcrmcs pinifolice Fitch. Tracheation. An unusual case of 

 coalescence. See page 107. 



Fig. 27. Chermes pinifolice Fitch. Tracheation. An unusual case oi 

 coalescence. See page 107. 



Fig. 28 and Fig. 29. Chermes pinifolice Fitch. Two camera lucida draw- 

 ings of the same identical wing. Fig. 28 shows the tracheation of the freshly 

 emerged wing, and Fig. 29 shows the course of the veins Rs, M, Cu and 1st A, 

 twenty-four hours after Fig. 28 was drawn and after the tracheae had all become 

 invisible. See page 111. 



Fig. 30. Chcrmcs pinifolice Fitch. Normal tracheation of hind wing. See 

 page 116. 



Fig. 31. Chermes. Venation of both wings. 



PLATE XX. 



Fig. 32. Phylloxera sp. Venation of both wings. 

 Fig. 33. Psylla floccosa Patch. Tracheation of wing pad of nymph. 

 Fig. 34 and Fig. 35. Psylla floccosa Patch. Tracheation of freshh^ emerged 

 fore and hind wings. 



Fig. 36. Psylla floccosa Patch. Venation of fore wing. 

 Fig. 37. Trioza species. Venation of both wings. 



PLATE XXI. 



Euphalerns nidifex Scliwarz. Venation of fore wing. See page 1 19. 

 Pachypsylla celtidis Riley. Venation of both wings. See page 



Anomoneura mori Schwarz. Venation of forewing. See page 120. 



Pseudococcus citri. Venation. See page 123. 



Dactylopius species. Tracheation of freshly emerged wing. See 



Dactylopius species. Venation. See page 123. 



Alciirodcs sp. Tracheation of freshly emerged fore wing. See 



Alenrodes sp. Venation of forewing. See page 122. 

 Alenrodcs sp. Tracheation of hind wing. (Venation is identi- 

 See page 122. 



