BIOLOGY AND HUMAN WELFARE 



413 



into New England gives hope that it may eventually be conquered. 

 In one year alone nearly three million enemies, representing eight 

 species, were liberated. The Brown-tail Moth is another im- 

 portation from Europe whose activities thus far have been con- 

 fined to New England as the result, in part, of control measures. 

 These three examples may stand as representative of the legions 

 of destructive forest insects. (Fig. 262.) 



Finally we should be reminded, if necessary, that our households 

 are not immune to insect marauders that take an immense ag- 



Fig. 263. -- A, Camel Beetle, Anthrenus scrophulariae: a. larva of Carpet 

 Beetle; B, Clothes Moth, Tinea pellionella; b, larva of Clothes Moth. (From 

 Riley.) 



gregate toll each year. Carpet Beetles, popularly called Buf- 

 falo Moths, and Clothes Moths are all too familiar examples. 



(Fig. 263.) 



4. Beneficial Insects 



Although we have mentioned incidentally the part played by 

 certain insects in suppressing other noxious kinds, it would be 

 unfair to the insect world not to emphasize the existence of mem- 

 bers which are serviceable to Man: those thousands which prey 

 upon our enemies or supply us with materials. It has been well 

 said that "if insects would quit fighting among themselves, they 

 would overwhelm all Vertebrate animals"; though sometimes 

 long biological investigations are necessary to keep them fighting 

 when we have upset the natural conditions; e.g., moved them to a 

 new environment away from their natural enemies. Thus Acacia 

 plants brought from Australia introduced the Cottony Cushion 

 Scale which soon spread to the great California orange and lemon 

 groves, and entailed enormous losses. The fruit growers finally sent, 

 at their own expense, an expert entomologist to study in Australia 

 the native enemies of the Scale-insect. As a result some Ladybird 



