Question

In house fly, pseudotrachea are formed by
A. Rostrum
B. Haustellum
C. Basiproboscis
D. Labella

Answer 1

Based on the particular mode of feeding the insects have a wide range of mouthparts. The process of piercing and sucking are the two most important specialization techniques among the various types of existing ones which have evolved several times.

Complete answer: The major component of the floor of the mouth is the labium that is formed by the paired and fused secondary maxillae that is roughly quadrilateral structure. Labium maintains the function of assisting the food manipulation during the mastication by combining with maxillae.
Mouthparts of diphtheria mainly in those of the housefly family the labium forms the bulk of proboscis in which labella is present. A pair of fleshy labella is obtained when there is a distal expansion of the labium.
The main principle role of the labium in some insects is adopted as the special functions; jaws in the nymphs of Odonata, houseflies, dragonflies, and damselflies. Beneath the head and thorax labium is folded neatly in the insects but it snatches the prey and flicks back to its head where it can swallow with the mouthparts and chew completely.
Cibarium is the structure to which the labium is attached to its rear end in which the broad basal portion is divided into three main sub-regions namely submentum (proximal part) and mentum ( middle) and prementum (distal section) and further in the anterior portion.
Hence, the correct option is (D) Labella.

Note: Ligula is formed by the structure prementum that consists of a pair of inner lower called glossae and the lateral pair of lobes called the paraglossal. Lacinia and galea of maxillae are the homologous structures to paraglossal and ligula. The labial palps borne on the sides of the labium are the counterparts of maxillary palps. Labial palps aid the sensory function in eating like the maxillary pulps.