REPORT OF THE STATE ENTOMOLOGIST I913 39 



to nearby stems. Systematic cutting out of weakened plants is 

 advisable in most cases and, as a rule, no special expense will be 

 necessary to check this pest. 



Bibliography. An extended bibliography accompanied by a 

 record of distribution and food plants is given in Museum Bulletin 

 134, page 91, to which the reader in search of further information 

 is referred. 



CACTUS MIDGE 

 Itonida opuntiae Felt 



Species of Opuntia, the fiat-leaved, oval cacti, not the columnar 

 forms, may be injured by the deep red larvae of the cactus midge 

 and most seriously affected by a bacterial or fungous trouble which 

 gains access to the inner tissues through the injuries. The fungus 

 or bacterium is by far the most destructive and is apparently de- 

 pendent for favorable media, so far as cacti are concerned, upon 

 the work of the midge larvae. 



Signs of injury. Infestation is first indicated by an indistinct 

 swelling, usually at the base of a spine, presenting so few character- 

 istics that the person in charge of the plants and therefore familiar 

 with the work of the insect, could not be certain of the presence of 

 maggots without cutting into the tissues. This swelling gradually 

 becomes somewhat larger and eventually an opening appears. The 

 maggots work themselves out and either crawl down the plant or 

 drop to the ground. The desertion of the cacti is followed by an 

 infection which results later in a copious exudation of a mucil- 

 aginous fluid or sap which hangs in irregular masses an inch or so 

 in length (pi. 15, fig. 2). This infection is followed by the slow 

 death of the affected lobe and may eventually result in the destruc- 

 tion of portions of the plant or even entire plants. In some in- 

 stances the work of the maggots is inhabited by a small Ptinid beetle 

 belonging to the genus Catorama. 



Early history. This pest was first brought to our notice in 1909 

 by Mr George V. Nash, head gardener of the New York Botanical 

 Gardens. The species, according to his statements, occurs in 

 Opuntia banburyana from Italy and an Opuntia from the 

 British West Indies. Not much further was heard of this insect 

 until 1913, at which time it was characterized as a very serious pest 

 in a valued collection of cacti. Earlier it was thought that this midge 

 might be American, since the original distribution of the host plant 

 is limited to America, though subsequent statements would seem to 

 indicate that this insect may possibly be Italian in origin. Mr 



