< I VSSII l< \ : 



branous. minutely ret i. nlate. with ih.ir.i eoslal joint, (no 



areulus and triangle. Abdomen Render, with ten |6gU Cerci 



lamented. Nymphs a<juatiY; adulu predatory. Dr.- 



FIG. 23. Benacus griseus. Slightly reduced. 



PIG. 24. Head louse, 

 Pediculus capitis, female. 

 Length, 2 mm. 



and damsel-flies. Example, Libellula (Fig. 21). About two thousand 

 species have been described. 



PIG. 25. Hydrophilus triangularis. Natural size. 



9. Thysanoptera. Metamorphosis direct, but including a subpupal 

 stage. Eyes well developed. Mouth parts suctorial, in part a 

 metrical. Prothorax long, free. Tarsus one- or two-segmented 



