136 Objects for the Microscope. 



EMPIS STERCOBEA. 



A small, shining, yellowish fly, clothed with a few black 

 hairs or bristles ; the thorax with a black linear stripe ; 

 abdomen with three black stripes ; legs long, slender, and 

 yellow ; tarsi of a darker hue. The Empidae are a large 

 and very distinct family, containing twenty-three genera, 

 and are inhabitants of woods, hedges, fields, and gardens, 

 where they find their prey smaller Diptera, and all kinds 

 of lesser insects. They are fierce and voracious, transfixing 

 their prey with their long proboscis, and sucking out the 

 juices with their beautiful up-curved tongue. The eyes of 

 a male Empis touch one another ; those of the female are 

 parted by a narrow front, a distinguishing mark of the 

 sexes in most flies. The antennae of the Empis always 

 stand forward, and observe how diiferent they are from 

 those of either Dolichopus or Scatophaga. It is only by 

 thus comparing one slide with another that we learn our 

 lesson well. 



The antennae are five-jointed, close to each other at the 

 base, porrect, that is, standing out ; the first and second 

 joints bristly : first cylindrical; second cyathiform, or cup- 

 shaped, about half the length of the first ; third, subulate 

 compressed ; the fourth very minute ; the fifth like a style, 

 pointed sharply. The thorax has a broad, black stripe ; 

 abdomen three black stripes, and every segment is punc- 

 tured with a double row of light dots. The legs are long ; 

 the coxa shorter than the femur, the trochanter very 

 distinct ; the third joint of the leg, femur, or humerus, is 

 usually the largest and most conspicuous ; generally 

 speaking, the anterior pair are shorter and smaller than 

 the posterior pair. If the insect leaps, the thighs of the 

 hind-legs are very much thickened for the development 

 and action of its muscles. This is particularly seen in the 

 legs of the small beetle called Turnip-flea (Haltica), in the 

 flies Ascia podagrica, one of the Syrphida3, and also in 

 Syritta pipiens, which should be mounted as examples of 

 the thickened and toothed femur, and of a curved tibia 

 joint. The Ascia is very common in the month of June, 



