THE ORDERS AND FAMILIES OF INSECTS 



'1YSTE1!ATIC entomologists do not all agree on tne arrangement of 

 orders and families. As further study Is given to the groups, 

 changes are frequently found necessary. The following list 

 should not be understood to be the arrangement, but one arrange- 

 ment of the orders and families. It Is the order which Is fol- 

 lowed In arranging the specimens and records of the Iowa Survey 

 Collection. With the hope that It will Increase the usefulness 

 of this list for others, brief descriptions of many of the families have 

 been added. With some families the number of known Iowa species Is given. 

 This Is the number In parenthesis Immediately following the family name. 

 Since many species new to the state are being added to the survey collection 

 and records all the while, these numbers will be out of date even before be- 

 ing printed. 



I Order THYSANURA (The Briftle-Talls) 



*(Insec-cs of New York) 



1. llachllldae Active leaping forms about one-half Inch long. 



Found among stones. 



2. Leplsmatldae Sllverflsh, Flrebrats. Soft, thickly-scaled, 



about one- third Inch long. 



3. Campodeldae Small, white; -ander stones. 



4. Projapygldae Small; under stones. 



5. Japygldae Delicate, small; under stones. 



II Order COLLEMBOLA (The Spring-Tails) 



* (Collembola of Iowa, Mills) 



1. Podurldae (48) Elongate, flat antennae no longer than head; 



in decaying vegetation, etc. 



2. Entomobryldae .... (56) Elongate, distinctly segmented, antennae 



longer than head. 



3. Neelldae (1) Body subglobose, antennae shorter than head. 



4. Smlnthurldae (28) Body subglobose, antennae longer than head. 



Ill Order PLECOPTERA (The Stone Flies) 



*(Plecoptera of rl. A., Needham and Claassen) 



1. Pteronarcldae .... Large, many veins In wings. 



2. Peril dae Fewer veins In wings; around water. 



3. Nemourldae Usually small dusky species. 



4. Capnlldae Small, dark; often on snow In early spring. 



IV Order EPHEMERIDA (The May-Flies) 



*( Insects of New York) 



1. Ephemeridae Appear In Irmense flights along our rivers and 



lakes. 



*Book In which the catalog numbers for the order are found. 



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