150 Journal New York Entomological Society. [Voi. xxiv, 



are of tropical or sub-tropical origin, having been introduced at 

 various times from such localities and afterwards flourishing in an 

 atmosphere approaching that of their natural homes and containing 

 their native food plants. This is especially true of such species as 

 Pheidole anastasii Emery, Tetramorium guineense Fabr., Prcnolepis 

 fulva Mayr. subsp. piibens Forel and Isosoma orchidcarum Wst. in 

 the Hymenoptera, of Phytophaga violicola Coq., in the Diptera, of 

 Callopistria floridensis Guen., in the Lepidoptera, of Eiicactophagus 

 graphiptcrus Champ., in the Coleoptera and of the greenhouse roaches 

 in the Orthoptera. 



The 26 species which occur both in and out of greenhouses, are 

 practically all inhabitants of the upper austral zone which have at dif- 

 ferent times made their way into the greenhouses where different 

 conditions of temperature and moisture prevail and have become ac- 

 climated for short and long periods of time. In other words, each 

 species has simply followed its one or more food plants into the new 

 climate. 



The inability of the strictly greenhouse or tropical species to main- 

 tain themselves out of doors is undoubtedly due more to the absence 

 of proper food than anything else, this lack of food being as effec- 

 tive a check upon the spread of insects as climate, the food of course 

 also depending upon climate and soil. 



Thus, the insect fauna of a greenhouse really depends upon the 

 kinds of plants growing there. If the flora is tropical, most of the 

 insects will be also. If the plants are local growing as well outside 

 of as in the greenhouse, then the insects feeding upon them will be 

 local species. Out of a total of 81 species (including the Coccidae) 

 found in New Jersey under glass, two-thirds are strictly greenhouse 

 insects because most greenhouses are devoted to the growing of 

 exotic plants. 



It is a noteworthy fact that the majority of greenhouse insects 

 have not received the attention that they should from economic ento- 

 mologists and as a result most of the work done in combating these 

 pests is ineffective and worthless. Thus there is open to the economic 

 man, an almost virgin field, in which the factors of temperature and 

 moisture will play an important and vital part in successful control. 



