352 



THE INSECTS 



al space 



the larval or pupal case by a T-shaped break and has no frontal lunule (an oval sj 

 just above the root of the antennae). The Orthorrhapha are divided into: a. Nemo- 

 cera (with long, many jointed antennae) and b. Brachycera (with short antennae). 



The Nemocera are generally midge-like insects and have, as a rule, long slender palps 

 (mosquito). The Brachycera, however, are seldom midge-like. The antennae are 

 composed of only two or three simple joints with or without style or arista. The palps 

 are almost always short and never more than two- jointed. 2. Cydorrhapha: larvae 

 without differentiated head. The imago escapes through an anterior opening and has 

 a lunule and ptilinum (an inflatable projecting organ just above the root of the an- 

 tennae). If the halteres are covered by a scale (squama) we have calyptrate Cyclor- 

 rhapha; if not, acalyptrate. These squamae are large enough in the calpytrate species 

 to even conceal the halteres when the fly is looked at from above. 3. Pupipara: the 

 larvae are extruded from the mother and almost immediately begin the pupal life. 

 Leathery flies with poorly developed wings (Hippobocidae). 



The males of flies where the two compound eyes come together above the antennae 

 are referred to as holoptic, if more or less widely separated as dichoptic. Ocelli are 

 three single eyes usually, when present, situated in the triangular space between the 

 compound eyes in the front (the space separating the compound eyes). 



The anterior portion of the head which lies below the origin of the 

 antennae is the face and on each side of the face we have the cheeks 

 which should be studied as to presence of abundance of hairs. The 

 antennae which separate the front from the face are of great importance 

 in classification. In the Muscidae the appearance of a feathery struc- 

 ture, projecting from the terminal segment of the antennae, and called 

 the arista, is important. This may be bare or feathered and the 

 feathering may be only on one side or of one part. 



In studying the biting flies it is very important to recognize the anterior, small, 

 or mid-cross vein. This short transverse rib or vein is the key to wing venation. 

 Beneath it is the discal cell and it bounds the first posterior cell internally or basally. 

 The fourth longitudinal vein, which touches the bottom of the mid-cross vein, is of 

 particular importance as it gives different shapes to the first posterior cell as it runs 

 along the lower border of this cell. The closed-in discal cell is below the fourth 

 longitudinal vein. The character of the antennae should also be noted carefully. 

 The study of the bristles about head, thorax, and abdomen (chaetotaxy) is more 

 difficult. Anyone taking up the study of flies should carefully note the wings, etc., 

 of Musca domestica. By putting a few house flies on moist horse manure in a gauze- 

 covered bottle the entire metamorphosis may be observed. 



Tabanidae 



This is the family of horseflies, gadflies, breeze flies or green-headed flies. It 

 is the most numerous family of the Diptera there being more than 1000 species. 

 The females are blood suckers; the males live on flowers and plant juices. The 

 eyes are usually very brilliant in color, and in the male make up the greater part of 

 the head. 



