138 Objects for the Microscope. 



if a breeze had suddenly wafted them away, or invisible 

 beings had chased them ; then slowly and prettily they 

 re-flitted back again to commence their gambols. 



SYRPHUS PYRASTRI. 



Many of the Syrphidse are mounted whole ; they offer a 

 great variety in the structure of the antennae, the mouth 

 and the legs. Some are so large that the head only is 

 mounted, to show the beautiful eyes and labium, as Rhingia, 

 Helophilus, Eristalis, &c. 



They are our prettiest and commonest flies ; honey-loving, 

 flower-haunting, harmless little creatures. Most of them 

 are striped or banded black and yellow, and love to hover 

 in the air, over one spot, their wings almost invisible with 

 rapid vibration, accompanied by a shrill hum ; if alarmed, 

 they dart away with astonishing velocity, and are somewhat 

 difficult to catch. The family contains thirty -one genera ; 

 some of them so unlike the others as to require microscopic 

 observation and comparison ; the Eristalis, for instance, is 

 often mistaken for a Bee ; the Helophilus also, and Rhingia, 

 the two former abound in the autumn on the Michaelmas 

 Daisy, and the latter frequonf.s "the woods and hedges, dart- 

 ing like a Wild Bee into the flower-bells, with a long pro- 

 boscis, looking to the unassisted eye like a Bee's tongue. 



The two distinguishing characters of this large family 

 are these : the coalescence of the palpi with the maxillae, 

 and the spurious veins of the wing, one before the prcelrrachial 

 the other behind the pobrachial. The wing alone will 

 decide a Syrphus for a young entomologist ; therefore, in 

 examining this slide, let the chief attention be given to its 

 vein ing, also collect a lew varieties, comparing the wing of 

 the common Helophilus with this one of Syrphus pyrastri, 

 the type of the family. 



The costal vein ends at the tip of the wing, where it 

 receives the cubital. 



Mediastinal vein distinct, ending about the middle of the 

 costa. 



Sub-costal, continued nearer to the tip, and ending 

 separately in the margin. 



