_Midas giganteus_ is found in Brazil and adjacent countries in tropical America. It measures about one inch and a half in length. _Family 21, Nemestrinidæ._--These insects are chiefly inhabitants of tropical climates like the preceding family. They are generally of a black colour, sometimes with red legs. They suck the nectar of flowers through a long proboscis, but nothing is yet known of their transformations. [Illustration: Fig. 139.--Xylophagus Ater (Mag.)] [Illustration: Fig. 140.--Ceria Conopsoides (Mag.)] _Family 22, Bombyliidæ._--The Bee Flies belong to this family. They are small or middle-sized insects, densely clothed with hairs. They are exceedingly active insects with long tongues, with which they suck honey from flowers. Their _larvæ_ are often parasitic in their earlier stages on other insects. They are very useful in North America by keeping down the number of locusts, in the egg capsules of which the _larvæ_ feed. Two species, _Bombyliis major_ and _B. medius_, are common in this country, and may often be seen in gardens and open spaces in woods during the spring and summer months. _Family 23, Therevidæ._--This family is a very numerous one, especially those of the typical genus _Thereva_. They are slender, middle-sized black insects, and their bodies are generally covered with hair. They are generally found in the neighbourhood of bushes and trees. _Family 24, Scenopinidæ._--The _Scenopinidæ_ include a few minute, black flies, not exceeding a quarter of an inch in length. They are not very common, but are sometimes found about windows. _Family 25, Scroceridæ._--This family also contains small species of flies, but their metamorphoses are at present unknown. [Illustration: Fig. 141.--Medeterus Nolatus (Mag.)] They are usually to be found resting easily on dry branches of trees, but are generally rare. _Family 26, Empididæ._--The insects of this group are very similar to the _Asilidæ_ in their carnivorous propensities, but the species are usually of a much smaller size. _Empis livida_ is a common yellowish species measuring about one-third of an inch in length. [Illustration: Fig. 142.--Dolichopus Regalis (Mag.)] _Family 27, Dolichopodidæ._--This family is a very extensive one, including a considerable number of genera and species. They are usually small flies often of brilliant metallic colouring. They may be found generally in the neighbourhood of water. [Illustration: Fig. 143.--Scenopinus Fenestralis (Mag.)] _Family 28, Lonchopteridæ._--The species of _Lonchopteridæ_ are small yellowish-brown or greenish flies with lanceolate wings. They frequent the banks of shady streams, and are often found resting on wet stones. _Family 29, Syrphidæ._--The majority of flies belonging to this family are of a moderate size, and possessed of brilliant colours. With the exception of the enormous family _Muscidæ_, they are one of the largest families of the _Diptera_. [Illustration: Fig. 144.--Syrphus Ribesii (Mag.)]