350 



ZOOLOGY. 



The plant-louse (Pig. 330, Aphis mali Pabr.) 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, maie; female natural 

 size and enlarged. 



Fig. 339.— 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 

 Fig. 330.— cftn/soj)« and group of staiiced larvse resembling the adnlt. 

 *sgs. 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 Sialidm {Oorydalus) and the Hemerobiidce (Chrysopa, 

 Mantispa, Rhaphidia, and Hemerohius). 



Order 10. Mecaptera. — 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 difEer from tlie Neuroptera in the caterpillar- 

 tike 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. TricUoptera. — The group of caddis-flies, whose 



