350 



ZOOLOGY. 



The plant-louse (Fig. 330, Aphis mali Fabr.) is provided 

 with two tubes on the hind-body from which honey-dew 

 drops, which attracts ants, wasps, etc. In summer the 



Fig. 328. Cochineal in- 

 sect, male; female natural 

 size and enlarged. 



Fig. 329. Apple Aphis. Natural size and 

 enlarged. 



plant-lice reproduce asexually, and as there may be nine or 

 ten generations, one virgin aphis may become the parent of 

 millions of children and grandchildren. 



Order 9. Neuroptera. We now come to insects with a 

 complete metamorphosis. All the foregoing orders are 



ametabolous, the species 

 passing through an incom- 

 plete metamorphosis, the- 

 larv resembling the adult. 

 This order is now restricted 

 to those net-veined insects with a complete metamorphosis, 

 the mouth-parts free, adapted for biting, with the ligula 

 entire and large, broad, flat, and rounded, while the pro- 

 thorax is large, broad, and square. The group comprises 

 the SialidcB (Corydalus) and the Hemerobiidce (Chrysopa, 

 Mantispa, Rhaphidia, and Hemerobius).* 



Order 10. Mecoptera. The scorpion-flies are represented 

 by a single family (Panorpidae), with the typical genera 

 Panorpa and the wingless Boreus. They are net-veined 

 insects, but differ from the Neuroptera in the caterpillar- 

 like larvae and in the imagines having a minute rudimentary 

 ligula, the head being elongated, with minute mandibles 

 at the end of the snout. The maxillae are long, and connate 

 with the labium. 



Order 11. Trichoptera. The group of caddis-flies, whose 

 f See Hagen's Synopsis of North American Neuroptera. 



