1.
Primarily wingless-evolved from wingless
ancestors
Winged or secondarily wingless- evolved
from winged ancestors. e.g. Flea, head
louse, bed bug.
2.
Metamorphosis is totally absent or slight.
Present.
3.
Mandibular
articulation
in
head
is
monocondylic i.e., single
Dicondylic i.e., double.
4.
Pleural sulcus in thorax is absent.
Present.
5.
Pregenital abdominal appen- dages present. Absent.
Insect Morphology and Systematics
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101
The subclass Apterygota has 4 orders namely
1. Thysanura - Silverfish (Thysan-fringed, Ura-tail)
2. Collembola- Springtail or snowflea (coll-glue; embol-peg)
3. Protura - Proturans or Telsontail (Pro-first, Ura-tail)
4. Diplura - Diplurans or Japygids (Di-two; Ura-tail)