XIX INSECTA : RHYNCOTA 293 



damage to the plants on which it feeds. ^ The Mussel Scale 

 insect is common on apple trees. 



Classification of the Rhyneota mentioned in Chapter XIX. 



Order. Rhyncota or Hemiptera. 

 Sub-order 1. Heteroptera. 



Series A. Aquatic forms with small hidden antennae. 

 Genus 1. Nepa, the Water Scorpion. 



„ 2. Bcmatra,, the Water Stick Insect. 

 „ 3. Notonecta, the Water Boatman. 

 „ 4. Oorixa. 

 Series B. Forms with long antennae, living on the surface 

 of. water. 

 Genus 1. Gerris, the Pond-skater. 

 „ 2. Velia, the Water Cricket 

 „ 3. Hydrometra, the Water Measurer or Water 

 Gnat. 

 Sub-order 2. Homoptera. 



Family 1. Aphidae. Green-fly and Bark-lice. 

 „ 2. Gercopidae. Frog-hoppers. 

 ,, 3. Goccidae. Scale Insects. 



Practical Notes on Rhyncota 



1. Collect from a pond with a dipping net, any of the water- 

 bugs mentioned in this chapter. Examine them carefully and keep 

 some for a few days. Remember nearly all are carnivorous, and 

 therefore must be kept alone and fed on special animal food.^ 



2. Find Green-fly in any garden, and work out its life-history. 

 Isolate one insect and determine its rate of multiplication. Try 

 and distinguish the difl'erent kinds of Aphides, making use of such 

 books as Professor Miall's Injurious and Useful Insects, and also the 

 monograph on Aphides, by Buckton, in vol. iv. of the Ray Society 

 Publications. 



3. Search spruce and larch trees in the autumn for hibernating 

 female Ghermes, and for the clusters of eggs. Try and work out 

 their complicated life-history, protecting a twig, where eggs have 

 bee(P found, with a muslin bag, and visiting at intervals during 

 the following ten months to note what changes have occurred. 



^ For an account of this form see Injurious and Useful Insects, by 

 Professor Miall. 



^ For identification of specimens see Hemiptera Heteroptera, by E. 

 Saunders (1892). 



