194 INJURIOUS AND USEFUL INSECTS 



generation of hibernating females. From these in the follow- 

 ing summer winged females may proceed, wingless forms 

 being regularly produced at the same time. The winged flies 

 make their way back to the spruce, and from their eggs are 

 hatched true males and females, capable of producing fertilised 

 eggs ; hence the winged generation born on the larch are 

 distinguished as the sexuparous females. Each fertilised 

 female lays a single egg in autumn, and from this issues a 

 hibernating female, such as that with which we began. 



The scale-insects are very aberrant Hemiptera, to which, 

 however, wax-secreting aphids make some approach. Some 

 true scale-insects, such as Dactylopius and Orthezia, still 

 retain the power of moving slowly about. The foot in all 

 scale-insects is one-jointed, and ends in a single claw. The 

 males pass through a pupa-stage, and acquire wings, besides 

 minute halteres, or hind wings ; a few species are wingless ; 

 and one, the Chionaspis of the willow and other trees, has 

 both winged and wingless males (Newstead). Some scale- 

 insects secrete honey-dew, which is devoured by ants, wasps, 

 and other insects. 



The Anoplura (lice) are often regarded as a third sub-order 

 of Rhynchota. They are wingless parasites of mammals, and 

 have a minute sucking-tube for drawing up fluids, with a circle 

 of hooks around the base. 



NEUROPTERA 



The insects called Neuroptera in many entomological books 

 are a very puzzling group. To begin with, the word has no 

 constant signification. With some writers it denotes a large 

 primary division of insects ; others apply it to a collection of 

 a very few families. Those who give it a wide extension, 

 admittedly include in the order a number of families which 

 have no close affinity ; for the sake of practical convenience 

 they throw over the principle that classification should rest 

 upon demonstrated relationship alone. It seems to us so 

 anomalous to include dragon-flies, May-flies, scorpion-flies, and 

 lace-winged flies in one group, that we would rather submit to 

 the inconvenience of a mere enumeration which makes no 

 pretence to natural arrangement. No reason can be given for 



