DIPTERA. 505 
Latreille’s admirable group Tanystoma is cut up, as it appears to me 
unnaturally ; and hence, although there isa great hiatus between the 
Tipulidae and the Notacantha, and the antennz of some of the latter 
(Sargus, &c.) are aristate, I feel inclined to retain the Notacantha 
in the situation assigned to them by Latreille in his “ Genera.” 
From the peculiar construction and transformation of the Hippo- 
boscidz and Nycteribiidz, they are admitted by authors to forma 
distinct and terminal section of the order, under the name of Pupi- 
para ; the Cistride, Muscide, &c. having in several respects a nearer 
affinity with these than any other Dipterous insects, will occasion their 
near approach to them in the system ; whilst of all the remaining Dip- 
tera the Tipul and Culices, from their structure and transformations, 
are evidently the farthest removed from the latter, and at the same 
time nearest allied, both in their transformations and antenne, to some 
of the preceding tribes of insects.* The following distribution, there- 
fore, nearly resembles that of Latreille’s Genera, the families of the 
Tanystoma being transposed : — 
Section 1. Head always distinct from the thorax; claws of the tarsi not den- 
tated; larva annulose, not undergoing its transformations to the pupa state 
within the body of the parent; female insects oviparous (or laryiparous, some 
Muscide). 
Division 1. (Stirps 1.) Nemocrra Latr. Antenne composed of more than six 
joints; palpi 4 or 5-jointed ; pupa incomplete (Fam. Culicide and Tipulide). 
Division 2. Bracuocera Macg. Antenne short, nct having apparently more than 
three distinct joints; palpi 1 or 2-jointed. 
Stirps 2. Noracanrua Latr. Antenne apparently composed of only three 
joints, the last, however, being articulated ; proboscis exserted, seldom en- 
closing more than two lancets. The structure of the mouth is very incom- 
plete, and the number of the sete variable. Liatreille (Genera) gives only 
two as its character, but four in the Régne An. 2d ed.: in the former case 
and in metamorphoses, general appearance, and, as it would seem ( Régne An. 
p- 479., but see p. 485. contrd), in the variable form of the head of the larva, 
this stirps approaches the Athericera. Pupa coarctate, the skin of the larva, 
however, nearly retaining its previous form (Fam. Stratiomide, Beride, and 
Cenomyide). 
Stirps 3. Tanysroma Latr. Antenne with only three joints, ordinarily ter- 
minated by a seta (Tabanus excepted) ; proboscis exserted, generally with four 
sete (six in Tabanide ? ; mouth obsolete in Acroceridz) ; larva with a scaly 
head ; pupa incomplete (Fam. Tabanide, Bombyliide, Anthracide, Acroceride, 
Empide, Tachydromiide, Hybotide, Asilide, Mydaside, Therevide, Leptide, 
Dolichopide, and Scenopinide. i. 
Stirps 4. Arnericera Latr. Antenne with only two or three joints, ter- 

* Hence the species which have coaretate pupz and short setigerous antenne are 
evidently most typical of the order. 
