74 PROTECTION OF PLANTS, 1916-17 



Since the habits and life histories of the immature insects are so much 

 alike, and the enemies of one species of these moths are the enemies of all, 

 the mature moths of the different species show but slight structural differ- 

 ences, and the species of the same genus are often distinguished with dif- 

 ficulty. The genitalia, of course, are the most valid features but the colours 

 and markings of the fore-wings being fairly constant in each species are more 

 generally used as a basis for a synopsis. 



We have arranged the genera of the Crambidae of Quebec according 

 to the venation of the fore-wings — after the manner of Dr. Fernald — and 

 the species of the genus Crambus according to the predominant colour of 

 these wings. Since it is often difficult to distinguish gray from brown, or 

 brown from yellow, and as the markings in more than one case give us a 

 wing of no readily recognized predominant colour, many of the species will 

 be found in more than one division in the accompanying synopsis. The 

 proper position in every case may, however, be recognized since in it alone is 

 given the size of the moth. Such a form of key, giving repetitions which 

 may seem false or foolish to a person well acquainted with the species, has 

 been found advantageous in many keys of phanerogamous plants arranged 

 for beginners in botany, and should be of value to the tyro entomologist. 



Key to the Crambidae of Quebec 



1- — Fore-wings have veins 7, 8 and 9, arising from a common stalk, 2. 



1- — Fore- wings have veins 7 arising separately from the stalk of 8 and 

 9. — Argyria. 



2. — Antennae of male not plumed. — Crambus. 



2. — Antennae of male are plumed. — Thaumatopsis pexellus. 



Synopsis of Argyria 



1- — Brilliant-yellow oblique line crosses fore-wing, 13-20mm. — Aura- 

 tellaQU-A). 



1-— Three small yellow dots cross forewing, 18-22mm. — Nivalis (J-JC). 



Synopsis of Crambus 



1- — Fore- wings are gray or brownish-gray, 2. 



1.— Fore-wings are yellow or brown, 7. 



1. — Fore-wings are white, 21. 



2. — Fore-wings have indistinct or obscure markings, 3. 



2. — Fore-wings have interspaces of veins lined, 6. 



