228 Syrphidae. 



haired iii the usual way, only in ambiguum and dubium (Ihe latter 

 not Danish) with a curled hair near the tip of front femora in 

 the male, 



The genus is distinguished from Platychirus by the quile simple 

 legs in the male; also in the female this character may be used, as 

 the females of Platychirus have the front tarsi slightly broadened; 

 this is also the case in Melanostoma but to a very slight degree and 

 less than in Platychirus, but the character is, however, slight. With 

 regard to the Danish species the distinction is, however, easy, as the 

 peculiar triangular abdominal spots in the females of the two of our 

 species of Melanostoma are never found in Platychirus, and in our 

 third species the female has the abdomen almost unicolorous. — 

 The genus is very nearly allied to Platychirus, in faet, I think, so 

 nearly, that the species ambiguum (and dubium and fimbriatum) with 

 the special hairs on the anterior legs in the male, the broader head 

 with the antennæ placed higher above and the not quite small fifth 

 abdominal segment in the male almost stands as an intermediate 

 form, as also noted by Loew about this species {monochaetum) and 

 fimbriatum (Beschr. eur. Dipt. II, 224, Anm., 226, Anm.). 



The developrnental stages of M. mellinum are well known, and 

 Zetterstedt (Dipt. Scand. II, 1843, 756) bred M. tratisfugum from a 

 pear-shaped, dirty whitish pupa with black dorsal stripes and lateral 

 points; it was found on a leaf of Abies and developed on ^"/s. The 

 larva of M. mellinum is mentioned by Giard (Bull. Soc. Ent. de Fr. 1896, 

 234) and described as light green with a whitish dorsal stripe. They 

 were found in September on the umbels of Daucus carota, where they 

 attacked and sucked specimens of Musca domestica and Chortophila 

 imsilla, always attacking the prey in the neck between head and 

 thorax; when coUected they did not quit the prey before the next 

 or following day; they pupated and the imagines came after twelve 

 days. The author states that there were no Aphides on the Daucus, 

 and he mentions, that he has found the same species on Ghenopodium 

 album, feeding on Aphides, and he thinks that it is only exceptional, 

 that the larva takes other prey; he thinks that the larvæ were only 

 able to attack the flies when these were less mobile in the cold 

 morning. Ghapman mentions (Ent. Month. Mag. 2, XVI, 1905, 150) 

 the larva bred from eggs found on Veronica chamaedrys; these larvæ 

 fed on Aphides, among which the eggs were found, but they took also 

 Tortrix-\B.v\2id, when supplied with them and deprived of Aphides. 

 Grunberg (Die Siisswasserf. Deutschl., Heft 2, A, 1910, 206) records 

 that the larva of M. mellinum lives on Phragmites, probably of Aphides. 

 and that it hibernates within the reeds and pupates next spring. 



