The Colorado Beetle. 



i53 



inimical to the Colorado Beetle. The insect, says Riley, is 

 northern rather than southern in its native habitat. The 

 larvae, according to Riley, cannot withstand any great 

 variation in temperature ; they do not thrive, he says, where 

 the thermometer has a range of 100 degrees Fahrenheit. 

 Moreover, the larvae cannot stand a hot burning sun ; 

 they like a humid atmosphere. Its northern spread is 

 probably unlimited, until the arctic region is reached, for 

 prolonged frosts do not affect the hibernating beetles ; the 

 greater length of winter and the greater cold would only 

 reduce the number of broods. 



Yet we must not forget that the genus to which this beetle 

 belongs is southern rather than northern, the Colorado 

 Beetle itself occurring as far south as Mexico. It breeds and 

 flourishes in numbers in Kansas and in places where the 

 temperature has a still greater range, so that too much 

 reliance cannot be placed on Riley's statement referred to 

 above. 



Its Natural Enemies. 



A great number of natural enemies tend to check the 

 beetle in America. Amongst these are birds which feed 

 upon both larvae and adults, especially the Rose-breasted 

 Grosbeak [Gutraca ludoviciana). 



Both ducks and chickens, but especially the former, 

 devour the larvae. 



The Toad in America {Bufo Americana) gorges itself with 

 the grubs, and doubtless our British species would do the 

 same. 



Very numerous are the insect enemies recorded by Riley, 

 especially amongst the Beetles or Coleoptera, and the Bugs, 

 or Hemiptera-heteroptera. Strange to say, no members 

 of the Hymenoptera, the order that contains so many 

 parasites, are actually parasitic on Doryphora ; a single 

 species of Wasp {Polistes rubigtnosus. S. Feug), however, 

 occasionally provisions its nest with the larvae. 



Whilst examining the allotments at Tilbury, the large 

 Seven-spotted Ladybird {Coccinella septem-punctata) was 

 noticed in considerable numbers both in adult and larval 

 stages. The larvae were seen in one instance devouring the 



